MOSCOW -- After lengthy meetings with both Russian President Vladimir Putin and the country's foreign minister, U.S. Secretary of State John Kerry said Thursday that Washington and Moscow have reached an understanding on how the fragile cease-fire in Syria can be strengthened.
At a midnight news conference with Foreign Minister Sergey Lavrov, Kerry said this week's terrorist attacks in Belgium bolstered determination to bring stability to Syria. The Islamic State group, which claimed responsibility for the Brussels attacks, holds substantial territory in Syria.
The attacks "are a stark reminder -- they are a violent reminder of what we are trying to do," Kerry said.
Lavrov said, "We have agreed to continue co-ordinating activity toward fixing the cessation of hostilities regime."
Kerry said the U.S. and Russia will press for expanded humanitarian access in Syria and agreed that Syrian President Bashar Assad's government and its opponents need to begin releasing detainees as soon as possible.
They agreed on a schedule for drafting a political solution and said the next step in U.N.-brokered Geneva peace talks on Syria is to firm up how a political transition would work.
At the start of his meeting with Putin, which lasted more than four hours, Kerry hailed a cease-fire in Syria brokered by the U.S. and Russia, saying it had allowed Syrians "to taste and smell the possibilities of what it means to have a huge reduction in violence and to receive humanitarian assistance."
U.S. officials "obviously also have some ideas about this and how we can most effectively make progress in Geneva and begin the very serious and difficult work of the transition," Kerry said.
In a playful start to the talks, Putin noted that Kerry walked off the plane carrying his briefcase himself and joked that he may have brought some cash to bargain with Russia.
Kerry replied, "When we have a private moment I will show you what's in my briefcase and I think you will be surprised." He later told reporters that contents of his briefcase were "a secret" between himself and Putin.
In his comments, Putin said he hoped for a constructive discussion that would "allow us to make our positions on Syria and Ukraine closer." He also said progress on Syria that has been made so far was the result of President Barack Obama's position but did not elaborate.
The main Syrian opposition group wrapped up the latest round of indirect peace talks on Thursday by urging Russia to "use its leverage" on Assad's government to fulfil international hopes for a political transition.
The United States and Russia have been at odds over Syria since the conflict began more than five years ago, with Washington demanding Assad's ouster and Moscow saying it is up to the Syrian people to determine their leadership.
Kerry's meetings were arranged after Putin made a surprise announcement last week that Russian troops would partially withdraw from Syria after five months of military operations in support of Assad's government. After his meetings, Kerry said he had gotten a clearer idea of Putin's decision to withdraw.
Another current significant difference between the U.S. and Russia is the situation in Ukraine. Washington accuses Moscow of not doing enough to push pro-Russian separatists in the east to comply with a cease-fire. Russia, meanwhile, has complained that the Ukrainian government is dragging its feet on implementing the cease-fire.
Fighting in Ukraine's industrial heartland, which has close ties to Russia, has killed more than 9,100 people and left large swaths of land under rebel control. Germany, France and Russia mediated talks between the Ukrainian government and the Russian-backed separatists in Minsk, Belarus, which resulted in the truce agreement.
That has largely held, but none of the political elements, including calling a local election, has been implemented.
Kyiv insists it can't hold the vote because it cannot guarantee security for election officials. For their part, the rebels have said they won't allow Ukrainian right-wing parties to run, which the Ukrainian government says also makes the election impossible.
Kerry said he had raised concerns about a recent sharp increase in cease-fire violations and called on Russia to do more to get the separatists in line. Unless there is "true quiet" and full access for cease-fire monitors, U.S. officials say it will be difficult to get progress on other parts of the Minsk deal.
Kerry also said he had raised the case of Nadezhda Savchenko, a Ukrainian pilot who was sentenced to 22 years in prison in Russia on Tuesday on charges the U.S. says are false. Savchenko was convicted of complicity to murder in the 2014 deaths of two Russian journalists in eastern Ukraine, opening a door to a possible prisoner swap between the two countries.
The U.S. has repeatedly called for Savchenko to be released and Kerry did so again on Thursday. Ukraine has suggested trading two Russian prisoners for Savchenko and Kerry said he was optimistic that some progress on an exchange could happen soon.
Associated Press writers Jim Heintz and Vladimir Isachenkov in Moscow contributed to this report
