A US killer drone carried out an attack in the Yemeni province of Baida, killing nearly 20 people on the ground. A Yemeni security official confirmed on Saturday that the terror drone targeted a vehicle travelling towards the Southern province of Shabwa on Saturday, Al-Alam reported. The United States is the only country that operates assassination drones in Yemen as part of its official targeted-killing program in Muslim countries. Over the past years, Washington has regularly used unmanned aerial vehicles for attacks and spying in several Muslim countries, including Afghanistan, Pakistan, Somalia and Yemen. The drone strikes have escalated significantly over the past months, which have resulted in a hike in anti-US sentiments in the targeted countries, with people holding numerous protests against the deadly aerial attacks. The airstrikes were initiated under former US president, George W. Bush, and have been stepped up under the administration of President Barack Obama. Washington claims the attacks target anti-US militants, but evidence on the ground shows that civilians are the main victims of such attacks. The United Nations says the assassination drone strikes pose a growing challenge to the rule of international law. The world body and several human rights organizations have already identified the United States as the world’s number one user of “targeted killings” largely due to its drone attacks in Pakistan and Afghanistan. The US terror drone operations reached its fifth anniversary in January having tallied up an estimated death toll of at least 2,400 people, and the massacre continues despite international criticisms.