BONN, Germany - The foreign ministers of France and Germany voiced cautious optimism Friday about the willingness of the Trump administration to engage on Syria, after new U.S. Secretary of State Rex Tillerson took part in talks on Syria on the sidelines of a diplomatic summit.

France's foreign minister, Jean-Marc Ayrault, said the meeting Friday in Bonn, Germany, was “particularly useful,” noting that it came a week before the U.N.-backed peace talks in Geneva are to resume.

“It is important and absolutely instrumental for us to have a close dialogue with the United States on the Syrian issue and on many other issues,” Ayrault told reporters.

His German counterpart, Sigmar Gabriel, said Tillerson had “participated vigorously” in the discussion, which also included top envoys from Italy, Britain, Saudi Arabia, the United Arab Emirates, Qatar, Jordan and the European Union.

Gabriel said those who participated agreed that only a political solution could bring lasting peace to Syria, which has been shaken by war for almost six years.

Russia, which has provided military backing to the government of Syrian President Bashar Assad in its fight against a range of opposition forces, didn't take part in the talks on the sidelines of a two-day meeting of foreign ministers from the Group of 20 leading industrialized and emerging economies.

Gabriel noted, however, that Russia's support was crucial for progress to happen at the peace talks.

“On its own, the regime in Damascus won't conduct any serious negotiations,” he said.

Ayrault reiterated France's position that Assad can't be part of a future Syrian government, adding that Europe wouldn't finance the rebuilding of the country if he is.

Syria was one of several crises discussed by diplomats from the G-20 nations.

The G-20 was created in the late 1990s as a means of discussing global economic stability in a broader forum than the G-8 in the wake of the Asian financial crisis. The format gained further prominence when the heads of government met for the first time in 2008 in a bid to resolve the global financial meltdown.

Chairmanship of the group has rotated among the members and Germany is to host leaders in Hamburg on July 7-8.

The meeting in Bonn was the first opportunity for many foreign ministers to meet Tillerson and learn more about the Trump administration's future foreign policy.

“Everyone was happy that Rex Tillerson was there and took an active part in the discussion,” Gabriel told reporters. “Of course everyone knows, and the United States expressed this through their foreign minister, that we need international co-operation to solve existing crises in the world.”