ISLAMABAD, June 7: The United States embassy has warned its citizens of a threat of violence in Islamabad and surrounding areas and advised them to limit non-essential movements.

According to a warden notice, Americans living in Pakistan have been advised to take appropriate individual precautions to ensure their safety and security. The measures include maintaining good situational awareness, avoiding crowds and demonstrations and keeping a low profile.

After seizure of three explosive-laden vehicles in Rawal-pindi on Friday, the government had put law-enforcement agencies on high alert.

The notice said that Americans should avoid setting patterns by varying times and routes for all required travel and ensure that their travel documents and visas are valid at all times. US citizens should exercise caution in congested areas and if activity at a checkpoint appears suspicious or the checkpoint is overwhelmed, it was advised to seek another route, the notice said.

The US consulate general in Karachi had closed its public operations indefinitely owing to security concerns, the notice said, adding that Americans requiring emergency assistance should contact the consular section in the city. The notice said that US citizens were being encouraged to register with the embassy or the nearest consulate.

Security in and around Islam-abad, especially at foreign missions, installations and diplomatic enclave, has been beefed up.