Secretary of State John Kerry said at Wednesday's hearing that Arab counties have offered to pay for the entirety of unseating President Bashar al-Assad if the United States took the lead militarily.

"With respect to Arab countries offering to bear costs and to assess, the answer is profoundly yes," Kerry said. "They have. That offer is on the table."

President Obama's liberal activist base is adamantly opposed to military strikes in Syria, according to a new survey the Progressive Change Campaign Committee released Wednesday.

PCCC says more than 57,000 of its activists weighed in, and 73 percent of them opposed the U.S. taking action in Syria. Just 18 percent supported strikes, and just 14 percent said the U.S. should go ahead unilaterally if it can't find any allies.

Indeed, a majority of the activists don't believe Mr. Obama and Secretary of State John F. Kerry are being honest when they lay out their justifications for taking military action.

Russian President Vladimir Putin said on Wednesday the U.S. Congress had no right to approve the use of force against Syria without a decision from the U.N. Security Council, and that doing so would be an "act of aggression".

He said "anything that is outside the U.N. Security Council is aggression, except self-defense. Now what Congress and the U.S. Senate are doing in essence is legitimizing aggression. This is inadmissible in principle."

In remarks that could raise tension further before he hosts President Barack Obama and other G20 leaders on Thursday, Putin also said U.S. Secretary of State John Kerry lied to Congress about the militant group al Qaeda's role in the Syrian conflict.

President Obama took his case for intervention in Syria to the foreign stage on Wednesday, telling a Swedish audience - and a broader European community that has largely resisted American calls for support - that the "international community's credibility is on the line" as it decides how to respond to evidence that the Syrian government, under President Bashar al Assad, used chemical weapons to kill over 1,400 civilians.

Where the use of such weapons is concerned, Mr. Obama said, "I didn't set a red line. The world set a red line."

And the question the world faces, Mr. Obama said, is "Are we going to find a reason not to act? And if that's the case, I think the world community should admit it."

The president repeatedly stressed that the American intelligence community has "high confidence" that the chemical weapons attack on August 21 in a suburb of Damascus was perpetrated by the regime, reiterating much of the evidence his administration has presented to Congress and the American people.

As he has before domestic audiences, the president sought to demarcate the debate over Syrian engagement from the prior debate over the war in Iraq, which was attended by faulty claims of weapons of mass destruction.

Russian president says it is too early to say what Russia will do but does not exclude supporting a UN resolution

Vladimir Putin has warned the US against launching military action in Syria, stating that Russia has "plans" on how it would react if such a scenario unfolded.

The Russian president's comments came as Barack Obama for the first time portrayed his plans for US military action as part of a broader strategy to topple Bashar al-Assad, as the White House's campaign to win over sceptics in Congress gained momentum.

In an interview with Associated Press and Russia's state Channel 1 television, Putin said it was too early to talk about what Russia would do if the US attacked Syria but added: "We have our ideas about what we will do and how we will do it in case the situation develops toward the use of force or otherwise. We have our plans."

At the same time he said Russia did not exclude supporting a UN resolution on punitive military strikes if it were proved that Damascus used poison gas on its own people. But he described the idea that Syrian government forces would use chemical weapons at a time when he said they were in the ascendancy and knowing the potential repercussions as absurd. Given his comments, and the fact that Russia has protected Syria from punitive action at the UN security council before, his suggestion that Russia might support a resolution on strikes is unlikely to be given much credence in the US.

Mexican President Enrique Pena Nieto says reported surveillance by the U.S. National Security Agency would constitute an illegal act.

Pena Nieto demanded the United States investigate the allegations aired in a report Sunday night on Brazil's Globo TV.

The report cites 2012 documents from NSA leaker Edward Snowden indicating the U.S. monitored Pena Nieto's communications before he was elected in July 2012.

Pena Nieto spoke to reporters Monday at Canada's Gander International Airport in Newfoundland on a stopover during his trip to Russia for a G-20 summit.

Pena Nieto said that "if proved ... it is an act outside the law." He said he may discuss the issue with President Barack Obama at the summit.

Ahmad Nemah, a midlevel Syrian rebel commander, is certain there's sound military logic behind President Barack Obama's decision to delay U.S. missile strikes against the Syrian regime, but he's having a hard time persuading his subordinates. "I know that this is not a postponement but a strategic pause to . . . set up for a surprise attack," insisted Nemah, a former colonel in Syrian air force intelligence. "Of course, people are depressed, and I'm having trouble convincing everyone that there will be a strike."

There's a good reason why Nemah is having difficulty selling his argument to his fighters of the Free Syrian Army, the loose tangle of disparate guerrilla bands nominally backed by the United States and its European and Arab allies. Obama's abrupt decision on Saturday to delay the strikes that seemed just hours away is being seen in the region as the latest confirmation of an incoherent U.S. approach of mixed messages and unfulfilled threats that have driven America's standing to a new low.

"Washington doesn't understand the Middle East. His (Obama's) image here is of someone who is afraid of getting enmeshed in the machinations of the Middle East," said Maher Abu-Teyr, a political columnist with Ad-Dustour, a semi-official Jordanian daily newspaper. "There is no trust in Washington in the area because (people) think Obama is weak."

He cited a "constant change in rhetoric and hesitation" by the United States since the brutal conflict erupted in Syria in mid-2011. Among other missteps, he said, was the U.S. reluctance to take action early in the conflict that might have bolstered moderate rebel factions before the rise of al Qaida-linked groups, which now dominate the opposition.

"Obama should have moved in the first six months of the Syria crisis, not now," said Abu-Teyr. "Now, all of his choices are very difficult because he took all of this time."

Obama has shifted several times since the August 2012 "red line" he first set against Syrian President Bashar Assad's use of chemical weapons. After cautioning Assad against even moving a "whole bunch of chemical weapons around," he didn't enforce the warning when the regime allegedly was detected in December mixing components for the nerve gas sarin, or when in March the United States followed Britain and France in accusing Assad of having used chemical weapons "on a small scale."

'But our long-term national security will be impacted in a profound way and our humanity's impacted in a profound way.'

Brazil has canceled preparations for the visit of President Dilma Rousseff to the United States over reports she was the target of National Security Agency (NSA) surveillance, AFP reports.

A presidential spokesperson said a trip by a Brazilian delegation to prepare for the president's October 23 visit to Washington "was cancelled."

Following the spying revelations, a Brazilian official told Reuters on Wednesday that Rousseff was set to take punitive in addition to canceling the visit, which could include a halt on plans to purchase F-18 Super Hornet fighters from Chicago-based Boeing Co.

"She is completely furious," the official said.

"This is a major, major crisis .... There needs to be an apology. It needs to be public. Without that, it's basically impossible for her to go to Washington in October," the official continued.

On Wednesday, Brazil announced an investigation into domestic telecommunications firms had been launched to determine if they had illegally shared data with the NSA after it was discovered the agency had been spying on Rousseff.

U.S. President Barack Obama faced growing pressure from world leaders not to launch military strikes in Syria on Thursday at a summit on the global economy that was eclipsed by the conflict.

The Group of 20 (G20) developed and developing economies met in St. Petersburg to try forge a united front on economic growth, trade, banking transparency and fighting tax evasion.

But the club that accounts for two thirds of the world's population and 90 percent of its output is divided over issues ranging from the U.S. Federal Reserve's decision to end its program of stimulus for the economy to the civil war in Syria.

Russian President Vladimir Putin wants to use the meeting in a seafront tsarist palace to talk Obama out of military action against Syrian President Bashar al-Assad over a chemical weapons attack which Washington blames on government forces.

Obama wore a stiff smile as he approached Putin on arrival at the summit and grasped his hand. Putin also maintained a businesslike expression. It was only when they turned to pose for the cameras that Obama broke into a broader grin.

The first round at the summit went to Putin as China, the European Union and Pope Francis - in a letter for G20 leaders - aligned themselves more closely with him than with Obama over the possibility and legitimacy of armed intervention.