The Aleppo truce was brokered by Turkey and Russia earlier this month to allow the evacuation of civilians and was hailed as a major turning point in the nearly six-year war.
If successful, the latest proposal would form the basis of upcoming political negotiations between Damascus and the opposition, overseen by Russia and Turkey in the Kazakh capital Astana, Anadolu added.
Ankara has hosted a succession of closed-door talks between Russia and Syrian opposition rebels over the last weeks.
Qatar-based channel Al-Jazeera said a new meeting was planned on Thursday in Ankara, this time between Syrian rebels, Turkey and Russia.
Ankara and Moscow have been on opposing sides in the Syrian civil war, with Turkey seeking the ouster of President Bashar al-Assad, who is backed by Russia and Iran.
But the two countries have recently started to cooperate more closely on Syria, especially after a deal to normalise ties battered by Turkey`s shooting down of a Russian warplane last year.
Turkey remained conspicuously quiet as Assad`s forces, backed by Russia, took control last week of Aleppo in the biggest defeat so far for the rebels.
The conflict began in 2011 as an uprising against Assad but quickly morphed into a civil war after the regime unleashed a brutal crackdown on dissent.
The war has killed more than 310,000 people and forced millions more to flee their homes.
`Cancer on a global scale`
In a speech in Ankara after the report on a nationwide ceasefire came out, President Recep Tayyip Erdogan made no reference to the plan, while Kremlin spokesman Dmitry Peskov said he did not have enough information to comment.
A Syrian rebel official confirmed to AFP that talks for a possible ceasefire were under way, but obstacles remained for any deal.
Labib Nahhas, foreign relations head for the powerful Ahrar al-Sham rebel group, said the faction was "aware of ongoing discussions between Russia and Turkey about a nationwide ceasefire".
He said rebel factions had not been presented with any official proposal.
"Russia wants to exclude Eastern Ghouta from the ceasefire, which is not acceptable," he said, referring to a rebel-held area outside Damascus.
Syria`s army has been advancing in Eastern Ghouta in recent months, and securing the area around the capital would be another major government gain after recapturing Aleppo.
An official from the High Negotiations Committee -- which oversees political talks of the Syrian rebels -- said there was no information about a ceasefire so far. There was also no reaction from the Syrian regime.
No date has yet been set for the Astana talks and Russian foreign ministry spokeswoman Maria Zakharova said the meeting was still at the planning stage.
But the direct involvement of Turkey and Russia comes as Erdogan is increasingly expressing impatience at the role of the United States in Syria.
Previous ceasefire plans had been brokered by US Secretary of State John Kerry and Russian counterpart Sergei Lavrov. They met with only temporary success and failed to lead to a solution for the conflict.
Erdogan on Tuesday launched one of his most bitter attacks on US and Western policy in Syria.
He accused the West of not just supporting Kurdish militia that Ankara regards as a "terror group" but even Islamic State (IS) jihadists.
In an angry statement, the US embassy in Ankara said: "Assertions the United States government is supporting Daesh (IS) are not true."
Meanwhile, air strikes carried out by unidentified aircraft killed at least 22 civilians, including 10 children, in a village held by IS in Deir Ezzor province, the Syrian Observatory for Human Rights said.
Incoming UN Secretary General Antonio Guterres said the conflict "has become a cancer on a global scale", while urging Washington and Moscow to overcome their differences to help end the crisis.