Croatian President Kolinda Grabar-Kitarovic (L) welcomes visiting Spanish Foreign Minister Josep Borrell in Zagreb, Croatia, May 29, 2019. (Xinhua/Luka Stanzl)

Top EU diplomat Josep Borrell is expected in Tehran on Monday, Iran's foreign ministry announced a day ahead of the visit, amid new tensions over the Iranian nuclear issue.

Borrell "will visit Iran tomorrow for the first time since taking office [in early december]. He is set to meet the foreign minister [Mohammad Javad Zarif] and other Iranian senior officials for consultations," foreign ministry spokesperson Abbas Moussavi said in a statement. 

Moussavi gave no details on when Borrell would arrive or how long he would remain in the country.

His visit comes amid heightened tensions between Iran and the West over the Islamic republic's nuclear programme. 

On January 24, Borrell called for a meeting of remaining states party to the 2015 nuclear deal in February in an effort to preserve the agreement, which has been crumbling since the US unilaterally withdrew in 2018. All parties "have reaffirmed their determination to preserve the accord, which is in everyone's interest," he said at the time. 

In 2015, Iran agreed to drastically reduce its nuclear program in exchange for a partial lifting of international sanctions. But the withdrawal of the US from the deal and its reimposition of biting sanctions deprived Iran of expected economic benefits and prompted Tehran to announce a series of steps away from its commitments under the deal.

The European parties to the agreement triggered a complaint mechanism in January in an attempt to urge Tehran to return to the full implementation of its commitments.