Russian President's Assistant, Yuri Ushakov, stressed Russia's firm stance on the crisis in Syria, reiterating that this stance is "principled".

"Russia's position on the Syrian issue is principled," Ushakov was quoted by Russia Today website as saying in a press conference in Moscow, noting that "there could be slight modifications to this position according to the developments, but the basis will not change."

The Russian President's Assistant pointed out that the developments in Syria are always on the agenda of President Vladimir Putin's talks with the international leaders.

Ushakov noted that the latest response letter which President Putin sent to his U.S. counterpart Barack Obama includes Moscow's evaluations of the issues related to the U.S. missile defense systems and the Russian stances on Syria, Iran and Cuba among other issues.

He added that the Russian letter contains a number of suggestions and practical measures which President Putin has proposed to discuss with Obama, stressing that Moscow is not now waiting for a written letter from Obama "as now is the time for verbal talking."

Lukashevich: Russian-American Initiative on Syria Real Opportunity to Stop Violence

Earlier, Russian Foreign Ministry has described the statement adopted by Amman meeting of the so-called "Friends of Syria" as disappointing, stressing that carrying out the Russian-American initiative to hold an international Conference on Syria is a "real opportunity to end violence."

The Spokesman for the Ministry, Alexander Lukashevich, said in a press conference on Friday that Russia is doing its best to implement the US-Russian initiative on finding a peaceful solution to the crisis in Syria, noting that numerous communications are conducted by his country in this regard including the Syrian government and various representatives of the Syrian opposition.

He also indicated to the meetings and discussions conducted by his country with Western partners, particularly with the parties which contribute to surpassing the crisis in Syria, expressing regret over the presence of difficulties.

Lukashevich criticized the attempts of hindering the implementation of the Russian-US understandings on Syria and giving priority to the narrow political interests instead of the main goal which is represented by stopping the violence and ensuring the success of the international community's political and diplomatic efforts to start the Syria internal dialogue.

He warned that such attempts send negative indications to the opposition groups and push them to refuse dialogue, affirming that the successful start of the international conference on Syria requires the participation of all influential parties including the regional ones.

The Russian Official said the Syrian government had agreed in principle to participate in the proposed Geneva 2 conference.

"We note with satisfaction that we have received an agreement in principle from the Syrian government to attend the international conference, in the interest of Syrians themselves finding a political path to resolve the conflict, which is ruinous for the nation and region," Alexander Lukashevich said.

He added that the Syrian opposition should not miss the opportunity of holding the conference to end violence, stressing that the implementation of the Russian-American initiative is a real opportunity to end the bloodshed and suffering in Syria.