The Union home ministry on Monday night  advised the coastal states to take all precautionary measures to alert the people and remain in the 'highest state of preparedness'  after an earthquake  measuring 8.7 on the Richter scale hit off the coast of Sumatra in Indonesia.

In a message to the Chief Secretaries of Orissa, Andhra Pradesh, Pondicherry, Tamil Nadu, Kerala [Images], Karnataka, Lakshadweep and Andaman and Nicobar, the ministry said people living close to the sea may be moved up to safer places.

"There is a need to keep a close watch for another six to eight hours", it said.

The Ministry said a close watch was needed because the epicentre of the quake was North East of Sumatra and 'tsunami waves, if generated, may take little longer'.

The home ministry has asked the states to advise people to move away from the coastal areas to safer places.

Citing a report from the meteorological department, the ministry said the epicentre was in the seabed off the Sumatra coast and 'there is a possibility of this earthquake triggering a tsunami'.

Fishermen may specially be contacted and advised, it said asking the officials in the states to contact the Centre every hour and report the situation, steps taken and seek assistance if required.

Minister of Home Affairs Sriprakash Jaiswal, Home Secretary Dhirendra Singh, Disaster Management Secretary A K Rastogi are contacting authorities in coastal states and Andaman and Nicobar Islands.

People all along the coast in TN, including Kanyakumari, Nagapattinam and Cuddalore,  Andhra Pradesh and in Andaman and Nicobar are being evacuated.

With PTI inputs