The US has imposed travel restrictions for its employees in Pakistan following huge protests against a US-made anti-Islam film.
The restrictions have been introduced as anti-US demonstrations continued in Pakistan on Tuesday and more are planned in the coming days, Xinhua reported Tuesday.
"The US government has instituted travel restrictions for its employees throughout the country," the US embassy said on its website.
The alert says that the US government staff can now undertake essential travel only in Karachi, Lahore and Peshawar where it has consulates, besides Islamabad.
"We remind US citizens that demonstrations and protests in Pakistan are often spontaneous and can occur with little advance notice."
The message urged US citizens to avoid all demonstrations and maintain a low profile.
US citizens have also been asked to monitor the local news and maintain contact with the nearest US embassy or consulate by monitoring their websites for security updates.