U.S. and British officials deny the Iranians' claim indicating the countries may have supported the suspects, CNN reported Thursday.

Thirteen people died and more than 200 were wounded in the April 12 blast in Shiraz. Iranian officials initially the explosion on a homemade bomb, then said it resulted from improper handling of munitions, subsequently launching an investigation, CNN reported.

At the time, Iranian Minister of Information Gholam Hossein Mohseni Ejeie said there was no evidence of sabotage, CNN said, quoting from Islamic Republic News Agency, the official Iranian news agency.

But Ejeie Wednesday said the suspects had ties to several countries, including Britain and the United States, IRNA reported. Police arrested five people and reportedly recovered explosives and cyanide.

The minister said the Iranian Foreign Ministry alerted the countries reportedly linked to the suspects and the bombing. The countries didn't take action against the suspects, showed support for them instead, IRNA said.

The group allegedly was going to carry out similar bombings elsewhere in Iran, the minister said.