Russia President Vladimir Putin Thursday announced a nationwide ceasefire deal to come into effect across Syria from midnight and that the warring parties had agreed to sit down for peace talks.

The deal brokered by Russia and Turkey could represent a major breakthrough in nearly six years of war in Syria and comes a week after rebel resistance was crushed in the second city of Aleppo.

Although on opposing sides in the conflict, Turkey and Russia have been working intensively to find a ceasefire after the fall of Aleppo, in a process that conspicuously does not include the United States.

Putin said in televised comments that Damascus and the "main forces of the armed opposition" had inked the truce agreement and a document expressing a readiness to start peace talks.

"Several hours ago, the event occurred that we have not only been waiting for but been working so much to hasten," Putin said in a meeting with his defence and foreign ministers.

After the Kremlin announcement, Syria's army said it would halt all military operations from midnight, and the opposition National Coalition also said it backed the truce.

Putin also said he would reduce Moscow's military contingent in Syria, which has been flying a bombing campaign in support of President Bashar al-Assad since last year.

The Kremlin strongman, however, said that Russia would continue to fight "terrorism" in the war-torn country and maintain its support for the government in Damascus.

Russian Defence Minister Sergei Shoigu said that the seven opposition groups, including the powerful Ahrar al-Sham, that have signed up to the agreements after months of talks comprise some 62,000 fighters and control a large portion of territory in central and northern Syria.

He warned that any groups that did not abide by the ceasefire would be considered "terrorists" alongside the Islamic State group and the former Al-Qaeda affiliate previously known as Al-Nusra Front, now rebranded the Fateh al-Sham Front.

Putin's announcement of the deal came hours after Turkey's foreign minister said the potential truce could start by New Year.

The nationwide ceasefire follows the deal brokered by Turkey and Russia for Aleppo which allowed the evacuation of tens of thousands of civilians.


Astana talks

Moscow and Ankara are now pushing for peace talks between Damascus and the rebels to start soon in the capital of Kazakhstan, Astana.

"Now we need to do everything for these agreements to come into force, for them to work, so that the negotiating teams that have been or are being formed promptly and as soon as possible arrive in Astana," Putin said.

Russia and Turkey have both said that the peace talks they will supervise are meant to supplement UN-backed peace efforts, rather than replace them entirely.

Russian Foreign Minister Sergei Lavrov said that Russia, Turkey and Iran were currently organising for the talks to begin in Astana and pressing for other key international players to get involved.

Lavrov said Moscow would invite Egypt before trying to attract other regional powers such as Saudi Arabia, Qatar, Iraq and Jordan.

In a clear snub to US President Barack Obama, Russia's top diplomat said Moscow would look to get the team of President-elect Donald Trump in the mix when he takes power next month.


Fighting continues

As its cooperation tightened with Moscow, Turkey stood conspicuously quiet as the regime, supported by Russia, took control last week of Aleppo, handing the rebels their biggest defeat in the civil war so far.

The victory was also a boost for Putin, who sent forces to Syria last year to bolster Assad in an unprecedented intervention.

Syria's conflict began with a 2011 uprising against Assad but quickly morphed into a complicated civil war that has now killed more than 310,000 people and forced millions more from their homes.

The conflict continued to rage as civilians were killed in regime strikes on Thursday, the UK-based Syrian Observatory for Human Rights told AFP in Beirut.

The observatory said At least 15 civilians, including six children, were killed on Thursday in air strikes and artillery fire on rebel-held territory near Syria's capital Damascus.