Itar-Tass reported that Lavrov, in a meeting with Mohammad Javad Zarif in Vienna on Sunday evening, said that President Putin intends to talk with his Iranian counterpart President Rouhani over the phone.

He added that process and results of the talks between Iran and Group 5+1 are among important issues to be discussed by the two sides.

Russian Foreign Minister Sergei Lavrov and his deputies met with Iranian Foreign Minister Mohammad Javad Zarif and his deputies in Hotel Coburg on Sunday evening.

Majid Takht-e-Ravanchi and Abbas Araqchi as well as Sergei Ryabkov attended the meeting.

Before the meeting, Zarif had met with US Secretary of State John Kerry. Zarif is to meet with his Chinese counterpart on Monday morning.

An official close to Iran's nuclear negotiating team said that Foreign Minister Mohammad Javad Zarif and his US counterpart John Kerry have discussed ways to continue the negotiations on Sunday evening.

He told IRNA that in the direct meeting between Zarif and Kerry, they discussed different nuclear issues and ways to solve them.

After five rounds of tripartite talks between Zarif, Kerry and Catherine Ashton, the two foreign ministers in a bilateral meeting discussed issues of mutual interest for 75 minutes.

Zarif had met with US Secretary of State John Kerry

It was the first bilateral meeting between the two foreign ministers after victory of the Islamic Revolution.

British Foreign Secretary Philip Hammond says Iran and the P5+1 group will make a "last push" for a comprehensive agreement on Tehran’s nuclear program before a November 24 deadline.

"At the moment we're focused on the last push, a big push tomorrow morning to try and get this across the line," Hammond told reporters on Sunday.

Iran and the Sextet of world powers -- Russia, China, France, Britain, the US, and Germany -- have been holding talks in Vienna over the past six days to hammer out a comprehensive deal on Tehran’s nuclear program. Diplomats say the two sides have made progress but big gaps still remain.

Sources close to the Iranian negotiating team say the main stumbling block in the way of resolving the dispute over Iran’s nuclear energy program remains to be the removal of all the bans imposed on the country, and not the number of Iran’s centrifuges or the level of uranium enrichment.

Tehran wants the sanctions entirely lifted while Washington, under pressure from the pro-Israeli lobby, insists that at least the UN-imposed sanctions should remain in place.

French Foreign Minister Laurent Fabius, US Secretary of State John Kerry, former EU foreign policy chief Catherine Ashton, the High Representative of the Union for Foreign Affairs ,Britain's Foreign Secretary Philip Hammond and German Foreign Minister Frank-Walter Steinmeier meet for the dinner at the residence of British ambassador in Vienna on November 23, 2014.

By arrival of Russian and expected china’s foreign ministers as like as Saud al Faisal Saudi Arabia foreign minister unexpected trip to Vienna for talking with john Kerry for updating the result of nuclear talks, It seems that all the parties involved in the negotiation are making every effort to sign a comprehensive agreement in the last day of November 24 deadline.

Although Iranian diplomatic source say that the extension of Tehran’s nuclear talks with six major world powers beyond the Monday deadline is not on the agenda of Vienna discussions but some diplomatic source indicating an extension.

The last confirmed source is the Chinese representative involved in negotiations on Iran's nuclear program which said on Sunday in Vienna that talks may need to be extended, as time is running out for a deal to be struck before Monday's deadline, CCTV reports.

Cheng Jingye, Chinese representative to the talks and envoy to the International Atomic Energy Agency (IAEA), said the sides involved are still focusing on reaching a deal by Monday, but that may not be enough time for the sides to come to an agreement.

"There have been some new ideas and suggestions during the talks. The deadline of this round of negotiations is Monday.

Considering that some issues are complex and important, I think more time may be needed," said Cheng.

"We have been working closely with other sides, such as the United States, Iran and Russia in the past few days. We've had many discussions within our framework, and China has been playing a constructive role in moving the nuclear talks forward," he added.

Earlier, an Iranian official told the Iranian Students News Agency (ISNA) that it would be impossible to agree on a comprehensive deal by Monday due to the time limit and amount of details yet to be discussed. U.S. Secretary of State John Kerry on Saturday said big gaps still remain between sides.

Some analysts remain confident a deal will be reached, although not necessarily before the deadline expires.

"We can be optimistic about reaching an agreement. It may not happen by November 24, but I think it shows that there is significant political will and commitment to getting a deal, even though we may need a short extension in order to get there," said Kelsey Davenport, an analyst at the Arms Control Association.