A senior adviser to Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei says Tehran and Moscow need to bolster their “strategic” cooperation in the face of US hegemony.

Speaking to reporters upon arrival in Moscow on Wednesday, Ali Akbar Velayati lauded Tehran-Moscow relations as “strategic,” expressing hope that his visit would be a turning point in bilateral ties.

“The current situation is very critical and the world is under the hegemony of a wayward person -- the US president who defies international regulations. Therefore, it is necessary that the cooperation [between Iran and Russia] be increased,” Velayati said.

He added that cooperation in the region between the resistance front led by Iran and Russia against terrorism and its supporters in Syria and other regional countries was indicative of an exemplary, strategic and long-term partnership between the two countries.

The former foreign minister also praised cooperation between the two countries in the international arena, including on the Iran nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA), as well as in defense, economic and security sectors.

Velayati said that he would deliver messages from Ayatollah Khamenei and Iranian President Hassan Rouhani to Russian President Vladimir Putin.

Iranian Foreign Ministry Spokesman Bahram Qassemi said on Tuesday that Velayati’s visit was part of efforts to make Iran's stance clear after the US pullout from the JCPOA signed between Tehran and the P5+1 group of countries in 2015.

US President Donald Trump announced on May 8 that Washington was walking away from the nuclear agreement, signed between Iran and the five permanent members of the United Nations Security Council -- the United States, Britain, France, China and Russia -- plus Germany.

Trump also said he planned to reinstate US nuclear sanctions on Iran and impose "the highest level" of economic bans on the Islamic Republic.

Qassemi said after Trump's “strategic mistake” to exit the multilateral and international accord, Iran decided to dispatch a number of its special representatives" to other countries to “carry messages of high-ranking" Iranian officials about the country's viewpoints and stance on the "selfish" US behavior which runs counter to international regulations.

The Iranian spokesperson explained that Velayati's visit to Moscow was in line with such a policy and noted that he would also travel to China.