DUBAI - Yemen's al-Qaida wing has stepped up operations in the southern flashpoint province of Abyan, its embassy in the United States said, taking advantage of a power vacuum as a rights group accused forces of unlawful killings.US-based group Human Rights Watch said in a statement on Saturday that Yemeni forces may have killed dozens of civilians in unlawful attacks while fighting an Islamist armed group in the southern province of Abyan since May 2011.