Russian President Vladimir Putin attends a news conference after a Syria summit, in Istanbul, Turkey October 27, 2018. Emrah Yorulmaz/Pool via REUTERS

ISTANBUL (Reuters) - There are no firm agreements yet regarding a possible visit by Russian President Vladimir Putin to Washington, Kremlin spokesman Dmitry Peskov told reporters.

The White House has formally invited Putin to Washington, U.S. National Security Advisor John Bolton said on Friday, returning to an idea put on hold in July amid anger in the United States over the prospect of such a summit.