And while the Syrian government voiced its support for the agreement, neither Damascus nor the Syrian rebels signed any deal.
Their chief gripe was the involvement of Iran, a country which has poured tens thousands of troops and fighters into Syria to fight rebel forces.
The negotiations in Astana are viewed as complementary to broader United Nations-brokered talks in Geneva on a political settlement, but neither have yielded real progress as of yet.
Full details of Thursday's agreement have not yet been released. "It's been a long time, but we will be working diligently, and I think there's a very, very good chance", Trump said during a joint press conference with Abbas at the White House.
"This is the key and core problem in the agreement".
The first and the largest safe zone in northern Syria will include the Idlib province and adjoining districts of Latakia, Aleppo and Hama with a total population of over 1 million, the ministry said.
Nofal said that the two leaders would discuss the results of the Arab League summit, which took place in Amman in March, as well as Palestinian issues and the fight against terrorism.
MOSCOW (AP) - A Russian plan to set up "de-escalation zones" in Syria is to go into effect at midnight on Friday, but it will be at least another month before all the details are worked out and the safe areas are fully established, according to Russian officials. The war-torn country believes in the Russian President and hopes for his continuing support.
Asked earlier this year to comment on the idea of safe zones after it was raised by President Donald Trump, U.N. Secretary-General Antonio Guterres pointed to tragic examples such as Srebrenica, a U.N. -protected enclave in the Bosnian war where 8,000 Muslim men and boys were massacred in 1995.
Analysts say that Moscow could be pushing the Assad regime to de-escalate the conflict and agree to the plan.
In an apparent challenge to the U.S., Russian President Vladimir Putin's envoy at the talks, Alexander Lavrentiev, said Friday that the U.S. -led coalition in Syria wouldn't be allowed to carry out bombing raids outside of eastern areas of the country where Islamic State forces are concentrated.
An global team set up to apportion blame for chemical weapons attacks in Syria has started investigating the deadly April 4 sarin gas attack in Idlib province.