UNITED NATIONS A UN human rights investigator has warned the United States that its use of unmanned drones to fight militants like those in Pakistan and Afghanistan may violate international law against summary executions. Philip Alston, a UN special rapporteur on extrajudicial, summary or arbitrary executions, said that unless the Obama administration explains the legal basis for targeting particular individuals and the measures it is taking to comply with international humanitarian law which prohibits arbitrary executions, It will increasingly be perceived as carrying out indiscriminate killings in violation of international law. The US, he said at a press conference in New York, should also indicate, in terms of domestic law, who was running the programme, and what accountability mechanisms were in place in relation to that or those organizations; what precautions it was taking to ensure that the weapons were used strictly for purposes that were consistent with international and humanitarian law; and what sort of review mechanism was in place to evaluate what had happened when those weapons had been used. Otherwise, the UN investigator said the result would be that the Central Intelligence Agency would be running a programme that was killing significant numbers of people with absolutely no accountability in terms of the relevant international laws. Alston, who is appointed by the UN Human Rights Council, said the US refusal to respond to UN concerns that the use of pilot less drones might result in illegal executions was an untenable position. He said his concern over drones, or predators, had grown in the past few months as the US military prominently used the weapons in the border areas of Pakistan and Afghanistan. What we need is for the US to be more up front and say, 'OK were prepared to discuss some aspects of this programme, the Australian law professor told reporters. Otherwise you have the really problematic bottom line, which is that the Central Intelligence Agency is running a programme that is killing significant numbers of people and there is absolutely no accountability in terms of the relevant international laws, he said. Pakistan has consistently denounced the drone attacks that have resulted in many civilian deaths. During a speech to a committee of the UN General Assembly earlier on Tuesday, Alston stepped up pressure for Washington to answer questions he first raised in June about the drones. He said the US could well be using the drones legally, but the country needed to be more open about the programme. The US told the Human Rights Council in June that it has an extensive legal framework to respond to unlawful killings. It also objected to Alstons criticism, saying the UN investigator did not have the mandate to cover military and intelligence. The response of the United States is simply untenable, Alston said. And that (US response) is that the Human Rights Council, and the General Assembly by definition, have no role in relation to killings that take place in relation to an armed conflict, he said. That would remove a great majority of issues that come before (the United Nations) right now.