Geneva, March 13 (RHC)-- The United Nations says the number of civilian casualties from U.S. drone strikes in Afghanistan has tripled in the past year. UN Special Rapporteur on Human Rights and Counter-terrorism Ben Emmerson warned on Wednesday that civilian deaths resulting from U.S. drone attacks are intensifying in Afghanistan.

The UN official said that at least 45 civilians were killed and 14 injured in drone strikes in 2013, triple the rate experienced in 2012. The Pentagon figures show the U.S. military launched more than 500 strikes from unmanned aircraft across Afghanistan last year.

The special rapporteur, a British lawyer who reports to the UN Human Rights Council (UNHRC) and the General Assembly, also told reporters in Geneva that around 500 civilians had lost their lives in drone strikes in Yemen since 2009.

On Monday, the UNHRC called for independent investigations into drone strikes in Afghanistan, Pakistan, Yemen and elsewhere. In a 21-page report, the UNHRC demanded the investigations after drone strikes around the world, mostly carried out by Washington, led to civilian deaths.

The U.S. is conducting illegal drone strikes in Pakistan, Afghanistan, Yemen, and Somalia. Washington claims that its airstrikes target militants, but local sources say civilians have been the main victims of the attacks. The UN has called the U.S. drone attacks targeted killings that flout international law.