LONDON — Two Iranian men conducted surveillance of a Manchester synagogue that was the site of a deadly attack a year ago as part of a plot to bomb it this year, a prosecutor said Saturday.

Salam Ahmadyan, 36, and Rahman Salehi, 34, researched attacking the Heaton Park Congregation Synagogue in Manchester in northwest England and the Jewish Museum in nearby Cheetham Hill, the court was told.

Ahmadyan and Salehi were arrested last month and charged Friday with engaging in conduct in preparation for terrorist acts.

Neither entered a plea during an appearance in Westminster Magistrates’ Court, where Judge Nina Tempia ordered them held until an Oct. 23 appearance at the Central Criminal Court in London.

Prosecutor Mark Luckett said the duo were directed by a third person believed to be in Iran who coordinated plans and provided instructions on making a homemade chlorine bomb.

The defendants were observed carrying out “a hostile reconnaissance within Manchester’s Jewish community,” Luckett said.

The Heaton Park synagogue was the site of an attack on Yom Kippur, the holiest day of the Jewish calendar, on Oct. 2, 2025, when Jihad Al-Shamie, 35, crashed his car into the gates and then began a knife attack while wearing a fake suicide belt.

Congregation members Melvin Cravitz, 66, and Adrian Daulby, 53, died in the attack and three other men were seriously wounded. Al-Shamie, who allegedly pledged allegiance to the Islamic State group, was killed by police.

Ahmadyan and Salehi entered the U.K. without authorization in the past six years after crossing the English Channel by boat, the court was told. Salehi was granted asylum and Ahmadyan has a pending asylum claim.

Vicki Evans, senior national coordinator of counterterror policing, said the plot was believed to be isolated and there was no ongoing public threat. She also said it was unconnected to a suspected terror plot at U.S.-runRAF Fairford air base, which some officials have said was linked to Tehran.

“I’m aware that the news of this alleged plot coming during the High Holy Day period has caused a great deal of concern,” Evans said. “It also coincides with the anniversary of the devastating terrorist attack last year at Heaton Park synagogue and comes in a wider context of increasing antisemitic incidents across the U.K., so we are very aware that this will likely increase what were already heightened concerns amongst the Jewish community.”