ISLAMABAD, Aug 13: Federal Minister for Interior Aftab Ahmed Khan Sherpao on Saturday said the US embassy in Islamabad recently received threatening anonymous letters after which the US government advised its citizens not to travel to some parts of Pakistan.

Talking to a group of journalists, he said that serious threats were given to the US citizens in those letters, which were sent by some unknown people.

Recently, the US government issued a warning to its citizens not to travel to Murree for security reasons.