US warns of attack threat against major hotel in Nairobi

The United States warned Thursday that extremists may be plotting an attack against a major hotel in Nairobi, urging its citizens to be cautious.

"The exact hotel has not been identified, but it is believed to be a hotel popular with tourists and business travellers," the State Department said in a travel alert.

The State Department urged US citizens to "exercise increased vigilance" if staying in hotels around Nairobi and to be aware of buildings' emergency evacuation plans.

Kenya has witnessed a series of bloody attacks carried out by al-Shabab, an extreme Islamist movement affiliated with Al-Qaeda that controls parts of neighbouring Somalia.

In 2013, a Shabab raid on Nairobi's upscale Westgate shopping mall left 67 dead in a siege that unfolded over four days.

Less than two years later, Shabab gunmen stormed Garissa University in northeastern Kenya, killing 148 people as they singled out Christians.

The bloodiest attack in Kenya's modern history was in 1998 when Al-Qaeda bombed the US embassy in Nairobi, killing 213 people.

Kenya sent troops into Somalia in 2011 as part of an African Union peacekeeping mission that helped drive Al-Shabab out of the capital Mogadishu.

The militants have warned Kenya to withdraw its forces.