LONDON - Iran's Supreme Leader Ayatollah Ali Khamenei has criticized President Hassan Rouhani for saying his detente policy with the West had caused the threat of war to fade as tensions intensify in Tehran before May election.

Rouhani, a pragmatist whose election in 2013 led to a diplomatic thaw between Iran and the West, championed in 2015 a landmark deal in which Tehran agreed to curb its nuclear activities in return for lifting of international sanctions.

A standoff between Rouhani, who is seeking a second term, and Khamenei's allies, who opposed the nuclear deal, has intensified in recent months ahead of the May 19 vote.

"Some say since we took office the shadow of war has been faded away. This is not correct," Khamenei was quoted as saying by the state media on Sunday.

"It's been people's presence in the political scene that has removed the shadow of war from the country," he added.

Rouhani faces competition from hardliners who have criticized his economic record, saying detente with the West and nuclear concessions had yet to yield economic benefits.

Rouhani urged voters on Saturday to prevent "extremism" returning to Iran, saying the country could face greater authoritarianism if he was replaced by a hardline rival.

Among Rouhani's challengers are Ebrahim Raisi, an influential cleric with decades of experience in the hardline judiciary, and conservative Tehran Mayor Mohammad Baqer Qalibaf, a former Revolutionary Guards commander.