A new video purportedly shows a group of fighters in Yemen pledging allegiance to the Islamic State (IS) and vowing to kill members of Yemen's Houthi rebel insurgency. The video marks the first official release from an active IS branch in Yemen.

The footage shows a group of masked men, who call themselves the Caliphate Soldiers in Yemen, firing Kalashnikovs, crawling through the sand, and marching in a desert area that the video claims is in Yemen. About halfway through the nine-minute clip, the apparent leader of the group vows to "cut the throats" of Shiite Houthis, the rebel group that toppled Yemen's government earlier this year.

"We have come to Yemen, with men hungry for your blood to avenge the Sunnis and take back the land they have occupied," the fighter says, followed by a call for all Sunni men in Yemen to join IS.

The video was released Thursday, soon after IS claimed responsibility on Twitter for a bombing Wednesday that killed five Houthi rebels in Ibb, a province that has also been the site of heavy bombing from Saudi-led airstrikes.

Yemen has plunged steadily deeper into chaos since January, when the Houthis took control of Sanaa, the country's capital. Pro-government troops and militias have been battling the Houthis, who have been accused of receiving support from Iran. The Houthis are also fighting al Qaeda in the Arabian Penninsula, the al Qaeda affiliate in Yemen. IS and al Qaeda are both Sunni and consider the Houthis to be heretics.

A Saudi-led coalition has been bombing the Houthis for more than a month in an operation called Decisive Storm, but the airstrikes have hit civilian areas and further added to the dire humanitarian situation in the country. On Thursday, Saudi Arabia announced plans to end the military operation, saying the country will work to achieve a resolution between the Houthis and Yemen's government through other channels.