A U. S. drone strike killed three suspected al - Qaida militants in southern Yemen on Saturday, according to local tribesmen. Believed to be the first drone strike this year in Yemen, it targeted the militants' vehicle while they were traveling in Shabwa province, the tribesmen said. They spoke on condition of anonymity because of security concerns. It was not immediately possible to verify their account. U.S. officials rarely comment on the covert drone program. The latest strike comes amid reports of divisions and defections among al-Qaida's rival group, the Islamic State affiliate in Yemen, as a defected group leader gave an online testimony, claiming that IS fabricated videos to exaggerate their strength and presence. In testimony posted online by al-Qaida supporters, a man calling himself Antar al-Kanadi said he defected from IS because its leadership had become too extreme. Al-Kanadi's allegations seem to match reports elsewhere of dissension within the Yemeni IS ranks. According to The Long War Journal, which monitors militant group activity, more than a dozen IS leaders and scores of their fighters have rebelled against the top leader, Abu Bilal al-Harbi, for alleged violations of Islamic Shariah law. "Seventy members of the Islamic State's Yemeni branch announced their 'defection' from the Islamic State's wali in a letter published online on Dec. 15," it said. Al-Kanadi also alleged that IS in Yemen released two videos of training camps in Hadramawt province and fraudulently claimed they were elsewhere in the country. Yemen has been mired in conflict between Shiite Houthi rebels and an internationally recognized government backed by a Saudi-led military coalition. Both IS and al-Qaida in Yemen have exploited Yemen's chaos and expanded their reach over the past year. Al-Qaida in the Arabian Peninsula has long been described by Washington as the global network's most active and dangerous branch. The IS affiliate in Yemen has claimed responsibility for a series of bloody attacks including four suicide bomb attacks on mosques in Sanaa in March and the assassination of the governor of Aden province.