HANGZHOU, China (Reuters) - Britain and Russia said on Sunday they hope to improve their relations through dialogue following the first meeting between new British Prime Minister Theresa May and Russian President Vladimir Putin.

Relations between London and Moscow have been strained by differences over Ukraine and Syria in addition to Britain’s complaint that flights by long-range Russian bombers near British air space have increased.

May said she hoped for an open dialogue with Russia even though the two countries have serious differences, speaking at the start of a meeting with Putin on the sidelines of a G20 summit in Hangzhou city in China.

“While I recognise there will be some differences between us, there are some complex and serious areas of concern and issues to discuss, I hope we will be able to have a frank and open relationship and dialogue,” May said.

Putin, in apparent reference to Britain’s decision to leave the European Union, told May that “everyone understands that you and your team are facing difficult challenges”.

“We wish you success and hope that we will be able to bring our bilateral relations to a higher level than they are at today,” he said.

The discussion between Britain and Russia touched on issues including terrorism, Syria, security and drug trafficking, Russian economy minister Alexei Ulyukayev said following the meeting.

“They have searched for common grounds on where the dialogue could be resumed,” Ulyukayev said.

In a telephone conversation last month, Putin and May agreed to meet to improve poor relations, expressing dissatisfaction about the state of ties, the Kremlin said at the time.