FILE PHOTO: U.S. President Donald Trump and Russia's President Vladimir Putin are seen during the G20 leaders summit in Buenos Aires, Argentina November 30, 2018. REUTERS/Marcos Brindicci

BUENOS AIRES (Reuters) - Russian President Vladimir Putin and President Donald Trump had a brief meeting on the sidelines of the G20 summit on Friday, Kremlin aide Yuri Ushakov said.

Ushakov said he met with U.S. National Security Advisor John Bolton. Russia and the United States were ready to continue contact, he said.

Ushakov said he was unsure of when Putin and Trump might meet next.