Islamabad: The US embassy has issued a warning to American citizens against visiting Marriott Hotel Islamabad for the next several days, in wake of a general threat. An advisory issued by the embassy said it was aware of a general but uncorroborated threat against the hotel, Dawn online reported. US citizens were advised to avoid the area for the next several days to allow time to assess the situation. Security of the hotel has been further tightened with police and troopers from Pakitsan Rangers patrolling around the building. "US citizens are urged to defer all non-essential travel to Pakistan. The mission reminds those citizens considering travel to or remaining in Pakistan despite this warning to enroll in the Smart Traveller Enrollment Programme (STEP)," the embassy said in a statement. It also stated that citizens "maintain vigilant situational awareness, avoid large crowds, keep a low profile and avoid visiting locations frequented by westerners. The citizens are strongly urged to avoid hotels that do not apply stringent security measures". Marriott Hotel, however, said foolproof security was in place. Assistant chief security officer of Marriott, Colonel (retd) Mohammad Zubair, said the US embassy had contacted the hotel administration and discussed the security arrangements. "The government has also taken the matter seriously and enhanced the security. Currently, both the police and Rangers are patrolling around the hotel," he said. Though Marriott is considered one of the safest hotels in Islamabad, it faced a suicide attack in September 2008 which left over 50 people killed and 250 injured.