ISIS has vowed to "liberate" Baghdad in a new propaganda video.

Catherine Herridge reported on "Happening Now" that a credible Twitter account associated with the terror group's leadership posted a clip saying it wants to take control of the capital of Iraq soon.

Herridge said that a counter-terrorism source said that the video is significant because it shows that ISIS remains steadfast in the face of efforts to beef up the U.S.-led coalition against it.

She added that the video comes just one day after President Obama said there is no "complete strategy" to fight the extremists.

Herridge reported that a separate ISIS media post claims that tribal leaders in the Iraqi city of Mosul, which was captured by ISIS a year ago, have now pledged their allegiance to the terror group and called out Iraqi politicians for failing them.

"A counter-terrorism source who tracks ISIS social media tells Fox News that the loss of the tribal leaders is a major blow because the U.S. had worked so hard to win their loyalty and support during the U.S.-led surge in 2007," Herridge said.

Watch the full "Happening Now" report above.

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