By Denis Pinchuk and Tulay Karadeniz | MOSCOW/ANKARA
Russian President Vladimir Putin announced a ceasefire between Syrian opposition groups and the Syrian government starting at midnight on Thursday.
The parties were also prepared to start peace talks, Putin said, after Moscow, Iran and Turkey expressed readiness to broker a deal to settle the nearly six-year-old Syrian war.
The Syrian army announced a nationwide halt to fighting but said Islamic State and ex-Nusra Front militants and all groups linked to them would be excluded from the deal. It did not say which unnamed groups would be excluded.
A spokesman for the Free Syrian Army, a loose alliance of rebel groups, said it would abide by the ceasefire, due to come into force at 2200 GMT, and take part in future talks.
"The agreements reached are, of course, fragile, need a special attention and involvement... But after all, this is a notable result of our joint work, efforts by the defense and foreign ministries, our partners in the regions," Putin said.
He also said Russia had agreed to reduce its military deployment in Syria, where its support has turned the tide in favor of President Bashar al-Assad in a war that has killed more than 300,000 and forced more than 11 million to flee their homes.
Putin spoke by phone to Assad who said he was committed to observing the ceasefire, the Kremlin said.
Turkey said it and Russia would guarantee the ceasefire.
"This window of opportunity should not be wasted," Turkish President Tayyip Erdogan said.
Three rebel officials told Reuters the deal excluded Islamic State, but did include the Jabhat Fateh al-Sham group, formerly al Qaeda's Syria branch, the Nusra Front - appearing to contradict the Syrian army's statement.
The Free Syrian Army spokesman said the ceasefire also does not include the Kurdish YPG militia, which has mostly avoided conflict with the Syrian government. The YPG could not immediately be reached for comment.
Russia's defense ministry said insurgent groups that signed the agreement included the powerful Islamist Ahrar al-Sham, Jaish al-Islam, which operates primarily near Damascus, and Jabha Shamiya, one of the main Turkey-backed FSA groups that had operated in Aleppo.
However, a spokesman for Ahrar al-Sham said it had reservations about the agreement and had not signed it.
The United States has been sidelined in recent negotiations and is not due to attend the next round of peace talks in Astana, capital of Kazakhstan, a key Russian ally.
Its exclusion reflects growing frustration from both Turkey and Russia over Washington's policy on Syria, officials have said.
However, Russian Foreign Minister Sergei Lavrov said the United States could join the peace process once President-elect Donald Trump takes office next month. He also wanted Egypt to join, together with Saudi Arabia, Qatar, Iraq, Jordan and the United Nations.
Washington said the news of a ceasefire was a positive.
"We hope it will be implemented fully and respected by all parties," State Department spokesman Mark Toner said.
The United Nations Syria envoy, Staffan de Mistura, welcomed the ceasefire announcement and hoped it would save civilian lives, enable the delivery of aid and lead to productive peace talks in Astana.
The deal should also help U.N. negotiations on Syria to be held in February, de Mistura's spokeswoman said.