The United States has ordered all non-essential government personnel to leave its consulate-general in the Pakistani city of Lahore.
A senior State Department official said the move on Friday was in response to a "credible threat" to the consulate. US personnel remaining in Lahore should limit non-essential travel within the country, they said.
On Thursday, the US issued a travel warning advising all American citizens to defer non-essential travel to Pakistan, the BBC reports.
"We are undertaking this drawdown due to concerns about credible threat information specific to the US Consulate in Lahore," the official said.
"An updated travel warning has also been issued. US citizens remaining in Lahore ... should limit non-essential travel within the country, be aware of their surroundings whether in their residences or moving about, [and] make their own contingency emergency plans."
Officials say the latest decision is not related to recent closures of several American embassies in the Middle East and North Africa.
The Pakistani authorities have been holding Lahore on a state of high alert, especially key government installations.
The troubled south-western city of Quetta has also been hit by a second attack in two days, with gunmen shooting dead at least nine people outside a mosque on Friday and targeting a funeral for a police officer on Thursday