President Donald Trump and Russia's President Vladimir Putin
© Steffen Kugler / Reuters
US President Donald Trump opened his much-anticipated meeting with Russian President Vladimir Putin by raising concerns about Russia's alleged interference in the 2016 presidential election, according to US Secretary of State Rex Tillerson.
"They had a very robust and lengthy exchange on the subject," Tillerson said after the two leaders met for two hours on the sidelines of the G20 summit in Hamburg, Germany.

"The president pressed President Putin on more than one occasion regarding Russian involvement. President Putin denied such involvement, as I think he has in the past," he said.
Russian Foreign Minister Sergey Lavrov confirmed that the two leaders discussed the subject.

"President Trump said he heard President Putin's unequivocal statement that [the allegations] are not true, and that the Russian government has not interfered [in the US election], and [Trump] accepts those statements," said Lavrov, adding that the US has not revealed any proof of such interference.

At a press conference in Poland on Thursday, a US reporter asked Trump to unequivocally say that Russia had interfered in the 2016 presidential election, but he declined.
"I think it was Russia, but I think it was probably other people and/or countries, and I see nothing wrong with that statement," he said. "Nobody really knows. Nobody really knows for sure."
The meeting, which was initially planned to last 30 minutes, went on for over two hours.

The leaders discussed many topics, including Ukraine, Syria, cybersecurity and fighting terrorism, according to Putin, who spoke at a news conference with Japanese Prime Minister Shinzo Abe right after his meeting with Trump.

Putin apologized to Abe for making him wait for about an hour.
"Both I and [the US president] owe you an apology," he said.
Meanwhile, Trump and Putin had "positive chemistry" during their first meeting, Tillerson said, adding that there was "so much to talk about" that neither leader "wanted to stop."

First Lady Melania Trump was sent into the meeting at one point to see her husband and "get him out," Tillerson also said. "Clearly, she failed," the top US diplomat joked, adding that the meeting went on for another hour after that.