Russia has been urging the United States to disclose the details of the deal on Syria, which came into force on Monday. It aims to end violence in Syria and allow for relief aid deliveries.

"The only reason why they apparently don't want to make it public is because the international community, as well as American and Russian public will immediately find out who is not abiding by the deal," Putin said in Bishkek, Kyrgyzstan.

"We agreed that al-Nusra Front should be distanced from the opposition and that their location should be disclosed as well as that of the so-called healthy [moderate] forces. What do we see instead? We see no separation of terrorists and healthy forces, but rather attempts by terrorists to regroup," he said.

"I wish we were honest with each other... And I do not quite understand, why we should conceal any of our agreements. Of course, we will not disclose them, until our US partners agree with it... I repeat that we have rather positive than negative attitude [to these agreements] and we hope the promises given by the US administration will be fulfilled."

Russia and the United States have reached an arrangement not to disclose the second part of the bilateral deal on the Syrian settlement so far, Russian presidential aide Yuri Ushakov said Saturday.

"The US asked us to keep these additional issues in secret so far. We are keeping the promise. We will see how the situation will develop given some parties to the negotiations are not aware of the details" Ushakov told reporters.

If the new ceasefire in Syria lasts for seven days, Russia and the United States will work together to establish a Joint Implementation Center and carry out joint airstrikes against terrorists in the war-torn country.

The US is still reluctant to take measures to force rebels under its control to implement the Syrian ceasefire, Russia's Defense Ministry said, adding that if things do not change, Washington will be the sole side responsible for the failure of the truce.

"After five days of the ceasefire, it has to be noted that only the Russian and Syrian sides have been fully implementing their commitments. On its own initiative, Russia prolonged the cessation of hostilities for 48 hours, and yesterday it was extended for another 72 hours," senior Russian General Staff official, Viktor Poznikhir, said at a briefing in Moscow.

But, according to Poznikhir, it is very different on the American side as "the US and the so-called moderate groups under their control didn't fulfill a single commitment undertaken in the framework of the Geneva arrangements."

The Russian official pointed out that "the main priority of the Russian-American agreements of September was the division of territories controlled by IS (Islamic State, formerly ISIS/ISIL), Jabhat al-Nusra, and the areas controlled by the 'moderate opposition,' as well the separation of the 'moderate opposition' from Jabhat al-Nusra."

Such a division is essential for the implementation of the ceasefire in Syria because "without it, the hands of the government forces are tied. They can't fight the terrorists without knowing which of them joined the truce and who didn't," he explained.

Numerous Russian appeals to the American side remain unanswered, which "raises doubts over the US's ability to influence opposition groups under their control and their willingness to further ensure the implementation of the Geneva agreements.

"Russia is making every possible effort to hold off government troops from the use of force in return [to opposition attacks]. If the US does not implement the necessary measures to fulfill their obligations under the September 9 agreements, the responsibility for the failure of the ceasefire will be solely America's," Poznikhir said.