Iranian supreme leader Ayatollah Ali Khamenei attends a meeting with lawmakers in Tehran, Iran, June 20, 2018. (Office of the Iranian Supreme Leader via AP)

TEHRAN, July 11 (Xinhua) -- Tehran and Moscow need to bolster their "strategic" cooperation in the face of U.S. hegemony, a senior adviser to Iran Supreme Leader Ayatollah Ali Khamenei said on Wednesday.

"The current (regional and global) situation is very critical and the world is under the hegemony of a wayward person, the U.S. president, who defies international regulations," Ali Akbar Velayati said upon arrival in Moscow.

"Therefore, it is necessary that the cooperation (between Iran and Russia) to be increased," Velayati was quoted as saying.

He also praised cooperation between the two countries in the international arena, including Syria issue, Iran nuclear deal, as well as on defense, economic and security sectors.

He expressed the hope that his visit to Russia would be a turning point in bilateral ties.

Velayati visited Moscow on Wednesday to deliver messages from the Supreme Leader Ayatollah Ali Khamenei and Iranian President Hassan Rouhani to Russian President Vladimir Putin.