Iran's President Ebrahim Raisi on Friday told his Chinese counterpart Xi Jinping that his country will not give in to "US bullying" in their first ever face-to-face meeting.

"The Islamic republic of Iran will not back down in any way in the face of US bullying," Raisi said according to a presidency statement, referring to Washington's sanctions on Tehran, mostly for its nuclear program.

The meeting, on the sidelines of a summit of the Shanghai Cooperation Organisation (SCO) in Uzbekistan, comes days after the European Union warned that negotiations to revive the 2015 nuclear deal between Iran and world powers are at a "stalemate".

China is one of the key members of the multilateral dialogue -- alongside France, Germany, Britain, Russia and the United States -- that is trying to revive the troubled 2015 nuclear deal.

"Despite all the enmities, the Islamic republic of Iran has never been stopped and will never be, and has been able to continue its path of progress and development," Raisi added.

The Iranian president also called for strengthening economic relations with China in the fields of "oil and energy, transit, agriculture, trade and investment."

Raisi also thanked China for supporting Iran's bid to gain full membership in the Shanghai Cooperation Organisation.

During his speech at the summit, Raisi said that "undoubtedly, US unilateralism seeks to hold countries back from their independent development path".

"The SCO needs to adopt new solutions and special measures to deal with unilateralism and cruel sanctions including forming lasting trade between the organisation's member states," he added.

Iran, one of four SCO observer states, applied for full membership in 2008, but its bid was slowed by UN and US sanctions imposed over its nuclear programme.

Several SCO members did not want a country under international sanctions in their ranks -- a situation that now applies to Russia as well.

At a conference in Tajikistan in September last year, members of the bloc endorsed Iran's future membership.

Iran's foreign minister Hossein Amir-Abdollahian said in a twitter post on Wednesday that he had signed documents in Samarkand pertaining to Iran's membership.