Iran's Foreign Minister Hossein Amirabdollahian will visit China by the end of the week to discuss the 25-year strategic agreement between two countries, the spokesman of the foreign ministry told a news conference in Tehran on Monday.

The visit comes as talks in Vienna aimed at reviving Tehran’s nuclear deal with world powers flounder.

Diplomats from countries that remain in the 2015 nuclear deal — Britain, France, Germany, Russia and China — are working with Tehran to revive the accord, which had sought to limit Iran's nuclear ambitions in exchange for lifting of economic sanctions.

American diplomats are present at the nuclear talks in Vienna but they are not in direct talks with Iranians. The accord collapsed in 2018 when then-President Donald Trump unilaterally withdrew the United States from the deal and re-imposed sanctions on Iran.

Iran and China signed a 25-year "strategic cooperation pact" in March last year to strengthen their long-standing economic and political alliance.

The accord brings Iran into China’s Belt and Road Initiative, a multi-trillion-dollar infrastructure scheme intended to stretch from East Asia to Europe.

The project aims to significantly expand China’s economic and political influence, and has raised concerns in the United States.