A day after Al Qaeda chief Osama bin Laden was shot dead in Pakistan's Abbottabad, the United States has indefinitely suspended visa operations from Pakistan.Visa services at US consulates in Lahore and Peshawar have been suspended, however, the US Embassy in Islamabad and US Consulate in Karachi are open for other business and for emergency American citizen services.An embassy note here said: "The U.S. Embassy in Islamabad and the Consulates in Peshawar, Lahore, and Karachi are closed for ROUTINE BUSINESS to the general public until further notice. (i.e. visas, etc.) The Embassy and Consulates remain open for other business and for emergency American citizen services."

The US on Monday said it was "inconceivable" that Osama bin Laden had no support system inside Pakistan. The Obama administration is investigating how the Al Qaeda chief was able to hold on in that country for so long.Bin Laden, the mastermind of the devastating 9/11 attacks on America, was tracked down and killed in a 40-minute operation by US forces in the garrison town of Abbottabad in Pakistan on Monday.