Iran said it took "decisive" action after a U.S. drone entered Iranian airspace in the Persian Gulf last week, a commander said.

"Iran will use all its capabilities, including the relevant international agencies, to follow up on this case," Maj. Gen. Ahmad Vahidi said Friday, according to Iran's semi-official news agency ISNA.

The Pentagon said two Iranian jets fired on an unmanned U.S. Air Force drone last week. But the United States said the firing happened over international waters on November 1.

The Iranian action triggered a formal warning by the United States to Iran through diplomatic channels.

The warning came after two Iranian Su-25 fighter jets fired on an unarmed Predator drone conducting routine surveillance in international airspace east of Kuwait, 16 miles off the coast of Iran, Pentagon press secretary George Little told reporters Thursday following CNN's report.