(Adds details of relations)
WASHINGTON, June 29 (Reuters) - U.S. President Donald Trump will meet with Russian President Vladimir Putin at a summit of world economic powers in Germany next week in their first ever encounter, a top U.S. official said on Thursday.
White House National Security Adviser H.R. McMaster told reporters that no agenda has yet been set for the meeting at the summit of G20 nations in Hamburg.
Allegations that Russia interfered in the U.S. presidential election last year and colluded with Trump's campaign have overshadowed the businessman's unexpected victory and have dogged his first five months in office.
The two nations are also at odds over the civil war in Syria where Moscow supports President Bashar al-Assad. The United States backs rebel groups trying to overthrow Assad, and Washington angered Russia by launching missile strikes against a Syrian government air base in April.
German Foreign Minister Sigmar Gabriel told Putin on Thursday that Germany hoped to bring him together with Trump at the summit.
Earlier, the Kremlin said Putin and Trump would meet on the sidelines of the G20 summit, but no separate talks were planned. "They will meet in any case there, on the sidelines of this summit, but no (separate) meeting is planned at the moment," Kremlin spokesman Dmitry Peskov told reporters.
On Wednesday, Russian Foreign Minister Sergei Lavrov said it would probably not be right if Putin and Trump did not talk at the summit. (Reporting by Roberta Rampton; Writing by Tim Ahmann and Alistair Bell; Editing by Diane Craft and Jeffrey Benkoe)