A senior USA state department official said earlier that a ceasefire deal could be announced as early as today.

Kerry said at the G20 economic summit in China that the talks have stalled over some "technical" issues but they would resume Monday.

Obama and Russian President Vladimir Putin were expected to interact during this week's Group of 20 summit, though a formal meeting was not on the books.

"We're not there yet", Obama said.

"It's fair to say that out of the review I think there are a couple of tough issues that we talked about today", Kerry said, declining to give details. The emerging deal is expected to also include provisions to ensure aid can reach besieged areas of Syria and steps to prevent Syrian President Bashar Assad's government from bombing areas where USA -backed rebels are operating.

And despite several rounds of global negotiations, a solution to the conflict that has killed more than 290,000 people and displaced millions remains elusive.

"I've said all along we're not going to rush", Kerry told reporters.

The president said Secretary of State John Kerry and his counterpart, Russian Foreign Minister Sergey Lavrov, "have been working around the clock, as well as a number of other negotiators, to see what would a real cessation of hostilities look like that could provide that humanitarian access and provide people in places like Aleppo relief".

The conflict has become increasingly complex, involving not only regime and rebels, but worldwide backers on both sides, Kurdish forces, militants and now Turkey.

Even as top diplomats vowed to keep trying, President Barack Obama expressed skepticism that an unlikely alliance between rivals would yield the breakthrough needed to end the 5-year-old civil war.

In return, the United States would coordinate with Russian Federation against Al-Qaeda, the letter said, without elaborating.

Part of Kashmir is under illegal occupation of Pak: MEA
Reiterating India's stand on Pakistan's involvement in the internal situation in the Valley, Swarup said Islamabad has no locus standi in commenting on that.

Russian Deputy Foreign Minister Sergei Ryabkov said on September 4 that "We are close to the deal".

On Sunday, intense aerial and artillery attacks helped government forces and their allies drive insurgents out of the Ramousah military complex in Aleppo, according to rebels and a monitoring group.

"We are talking about most serious issues of implementing a ceasefire", he added.

The attempted overthrow has led to accusations of USA involvement - and the tensions have been aggravated by clashes between Turkish forces and US -backed Syrian Kurds.

Speaking to the G20, Obama said: "It is a very complicated piece of business".

First would be grounding the Syrian air force and ending the barrel bombing of cities like Aleppo and Homs in order to allow humanitarian aid to reach millions of trapped civilians.

Obama, who met first Sunday with new British Prime Minister Theresa May, also planned to discuss Syria when he meets with Turkish President Recep Tayyip Erdogan, their first sit-down since the summer's failed coup in Turkey.

The U.S. has entered into cease-fire agreements with Russian Federation in the past, only to have them unravel. The Pentagon has backed the incursions, but said they should only be aimed at IS fighters.

"We will never allow the formation of an artificial state in the north of Syria", Yildirim said in a speech in the southeastern city of Diyarbakir, where he announced an investment programme to rebuild parts of the largely Kurdish region that have been destroyed by security operations.

"Many of the groups considered acceptable by the US have actually affiliated with the Nusra Front, while the Nusra Front is using them to avoid being attacked", Ryabkov told Russian media, citing a longstanding complaint of his government.