The threat came in a video posted on the Internet by Jund Al-Imam Al-Hujja, in which a group of masked gunmen appeared during a training with rockets, while a leader of the armed group made the statement, Anadolu agency reported.
"U.S. military and civilian bases have become legitimate targets for us," the masked man said, directing his message to U.S. President Donald Trump.
The speaker pointed out that the group's motive is based on a fatwa (religious edict) by prominent Iraqi Shia cleric Kazem al-Haeri.
On Friday, Al-Haeri accused Israel of carrying out drone attacks with support of U.S. forces in Iraq against the Shia Hashd al-Shaabi forces.
Roughly 5,000 U.S. troops have remained deployed in Iraq since the U.S. cobbled a coalition together in 2014 with the stated aim of fighting the IS terrorist group.
Last week, Israeli Prime Minister Benjamin Netanyahu hinted at Israel's involvement in the attacks against targets in Iraq.
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