TEHRAN, Iran - Three would-be ISIS fighters armed with explosives were arrested as they tried to cross Iran's border into Iraq, a senior Iranian police chief told state media Monday. They were caught as they attempted to slip across the northwestern border at night, Brigadier General Qasem Rezaei of Iran's border police told the FARS news agency.

“The three people had illegally crossed into Iran through one of it porous borders with the intention of crossing over to Iraq,” he was quoted as saying, adding that border police "have the technological visual and electronic capabilities of monitoring cross border movements” at night. No further details were immediately available.

The advance of ISIS in Iraq and Syria has created a common enemy for Iran and the United States. Tehran remains at diplomatic odds with Washington and joint action has been ruled out, but Iranian forces are separately fighting extremists inside Iraq even as the U.S. and its allies carry out airstrikes. A high-ranking Iranian officer was last week killed in the Iraqi city of Samara.

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