U.S. President Donald Trump crossed a “very dangerous red line” by killing Iran’s Supreme Leader, Ayatollah Ali Khamenei, Iran’s Deputy Foreign Minister Saeed Khatibzadeh said in an interview with CNN.

He noted that many Shia Muslims around the world would react to Khamenei’s killing. “From a religious aspect, he was a great religious leader, so many of Shiite followers across the region and around the world are going to react to that, and this is very obvious because President Trump passed a very dangerous red line,” Khatibzadeh said. “We have no option but to respond,” he added.

The official said Iran had approached Gulf countries with a proposal to shut down U.S. bases, which Tehran considers a threat.

“We communicated with them: either to shut down those American bases that are constantly threatening Iran and are constantly using to offend Iran, or we have no option just to push back,” he said.

Iran “cannot reach out to American soil, so we have no option just to attack any bases which is under US jurisdiction,” Khatibzadeh added.