ISLAMABAD  — The American embassy here on Thursday barred its staff from visiting restaurants and markets in Islamabad on the eve of Osama bin Laden’s death anniversary. The Al-Qaeda kingpin was killed in a US special forces raid in Abbottabad on May 2 last year and there are fears militants may mark the one-year anniversary with an attack.“Due to security concerns, the US embassy has restricted its employees from going to restaurants and markets in Islamabad April 27 - May 5,” a warning on the embassy website said. “We recommend that US citizens in Islamabad during this period take similar precautions.” The 9/11 mastermind’s three widows, their eight children and a grandchild are still being held in Islamabad after being detained in the Abbottabad raid. A US official speaking on condition of anonymity said the warning was issued in response to information about a specific threat. But an official said he had no information about a threat. “Also, based on the current security conditions and a significant increase in the level of sectarian violence in northern Pakistan, the US embassy has prohibited its employees from taking personal trips to the Gilgit/Skardu area until further notice,” the message said. The US embassy “continues to recommend that US citizens defer all non-essential travels to Pakistan,” the message further said.The mission asked Americans to refer to the US Department of State’s current travel warning for Pakistan and reiterated its advice to all US citizens to “take measures for their safety and security at all times, including practicing good situational awareness, avoiding of crowds, and maintaining a low profile”.It reminded US citizens that “even peaceful protests may become violent” and advised them to avoid protests.“US citizens should vary times and routes for all required travel. They should ensure their travel documents and visas are valid at all times,” it added.