WASHINGTON, Aug 9: A US senator asked the White House to explain how and why the name of an Al Qaeda informant was leaked to the press, amid concerns it had hurt the war on terror, a letter from the lawmaker showed on Monday.

A Pakistani intelligence source said on Friday that US officials confirmed the name of captured Al Qaeda suspect Mohammad Naeem Noor Khan while he was still cooperating with Pakistani authorities as part of a sting operation against Al Qaeda network, thereby compromising his cover.

It is not clear who was the first to disclose Khan's name, but his unmasking triggered criticism on both sides of the political spectrum, as well as speculation about the motives behind the leak. Security and terrorism are top issues for both parties in this year's US presidential elections.

"I respectfully request an explanation to me and any other member of Congress who might wish one of who leaked this Mr Khan's name, for what reason it was leaked, and whether ... reports that this leak compromised future intelligence activity are accurate," Sen Charles Schumer, a Democrat from New York, wrote in a letter to White House domestic security adviser Frances Town send on Aug 8.

A copy of the letter was obtained by Reuters on Monday. Information from computer expert Khan led the US to issue a high alert at financial institutions against a possible Al Qaeda attack recetly. -Reuters