SOCHI, Russia (AFP) - US Secretary of State John Kerry and Russian President Vladimir Putin held four hours of rare face-to-face talks on Tuesday as the two nations sought ways to cooperate after a sharp deterioration in relations.
The meeting during the highest level US visit to Russia since the Ukraine crisis erupted in late 2013 did not appear to result in any major breakthrough, though both sides expressed hope it could lead to improved ties.
Kerry's visit in itself was seen as a sign of the countries' willingness to improve relations.
A post on his Twitter account called the meeting with Putin "frank" and "productive".
Speaking after the talks in the Black Sea resort of Sochi, Russian Foreign Minister Sergei Lavrov and Kerry said Moscow and Washington should continue dialogue to try to resolve their differences.
"Today's meetings allowed us to better understand each other," Lavrov told reporters after talks on Ukraine and Syria.
Kerry, who also held another four hours of negotiations with Lavrov, said there was an "urgent need" for the United States and Russia to cooperate on confronting global challenges.
"There is no substitute for talking directly to key decision-makers, particularly during a period that is as complex and fast-moving as this is," he said.
He reiterated that biting US and EU sanctions on Russia could be rolled back, "if and when" the terms of a shaky Ukraine ceasefire were fully met.
Kerry insisted that all the terms of the truce had to be implemented - something Lavrov agreed with at a joint press conference.
While there were "certain contradictions and divergences as regards to the origins" of the conflict in eastern Ukraine, "we definitely shared the view that it is only possible to resolve" the crisis by implementing the truce, Lavrov said.
Pointing to the success of an earlier deal on eliminating Syria's chemical weapons, Kerry said: "There is an urgent need, we agreed, for that same kind of cooperation... the same kind of effort is now necessary on some other challenges that we face together."
Kerry warned all sides, including Ukraine's pro-Western government, that any further recourse to force would "be extremely destructive".
Despite badly damaged relations, Lavrov said: "We have an understanding of the need to avoid steps which can inflict long-term damage on bilateral ties in various fields."
"Especially if we take into account the fact that the solution of many pressing modern problems depends on our well-coordinated joint efforts on the international arena."
The Ukraine crisis is also likely to top the agenda at NATO foreign ministers' talks on Wednesday in Antalya, Turkey - Kerry's next destination after leaving Sochi late Tuesday.
IMPORTANT TO KEEP COMMUNICATING
On Syria, Kerry said that the two countries had agreed to share more information about continuing chlorine gas attacks by the regime of Syrian President Bashar al-Assad, which have raised alarm in Washington.
US officials said Kerry wanted to gauge whether Moscow's support for Assad may be on the wane as the rebels appear to be gaining the upper hand in the four-year civil war.
They also discussed Yemen and Libya, and Kerry briefed Putin on the negotiations on curtailing Iran's nuclear programme, saying it was important to maintain their unity on the issue.
He was accompanied by chief US negotiator Wendy Sherman, who will travel to Vienna on Wednesday for a new round of Iran talks.
Ties between Moscow and Washington were shredded when Russia seized the southern Ukrainian peninsula of Crimea in early 2014 and buttressed separatists in eastern Ukraine.
But signs are now emerging that both Russia and the West may be ready for a detente.