Qatar's Emir Sheikh Tamim bin Hamad Al-Thani attends the opening session of the 30th Arab League summit in the Tunisian capital Tunis on March 31, 2019.
Abu Dhabi CNN  — 

Qatar’s Emir Sheikh Tamim al-Thani met with Russian President Vladimir Putin on the sidelines of a conference in Astana, Kazakhstan, on Thursday to “defuse tensions” between Moscow and Doha, a source familiar with the talks, but not authorized to speak about them publicly, told CNN.

The United States and the European Union were briefed on the meeting before it took place, said the source.

“The purpose of the meeting between Qatar’s Emir and President Putin was to defuse the tensions between Russia and Qatar, which have grown following several events,” the source said.

A strain in the relationship between the two countries has emerged in recent months. The source said tensions have increased several times: after the Emir held a phone conversation with Ukrainian President Voldymyr Zelensky on Monday; after Qatar criticized Russia’s planned annexation of Ukrainian territory; and after Qatar’s participation in a meeting with NATO +8 countries in Germany in April.

The deteriorating relationship is now complicating Qatar’s diplomatic efforts in the region, the source said.

Qatar was attempting to help the revival of the 2015 Iran nuclear deal by relaying messages between Tehran and Washington. Separately, the tiny Gulf country was working with Russia and Turkey under a trilateral consultation process aimed at helping to find a political solution to the ongoing conflict in Syria.

“Qatar needs cordial relations with Russia and others in the region in order to be able to continue on various mediation and diplomatic files,” the source said.

During the meeting, the Emir told Putin that there is opportunity to strengthen the “historic ties” between Qatar and Russia on a political level and that there are “prospects” in energy cooperation, the Kremlin said in a statement.