India on Monday said there was no tsunami threat on its eastern coast after an earlier undersea earthquake off the Indonesian coast, but asked coastal authorities to be vigilant on Monday night.
"We have not issued a tsunami alert but have just asked the states to keep an eye on the situation," a senior disaster management official said.
"We are monitoring the situation but are not expecting any problems," he said. "There is no change in the sea level in the Indian Ocean."
A tsunami hit the Indonesian island of Java earlier on Monday, killing around 80 people and raising concerns that the vulnerable archipelago of Andaman and Nicobar in the Indian Ocean may also be hit.
"We haven't called back the tsunami warning, we are going to keep a vigil for the next 24 hours," senior official Ankita Mishra said from Car Nicobar island. "Thank God there was no tsunami."
Thousands were killed when the archipelago, closer to Indonesia than mainland India, was hit by the December 2004 tsunami, triggered by a massive earthquake.
"Police are urging everyone in coastal areas to stay away from the sea. No one is allowed to go to the harbour," said Anil Adhikari, a government official in Car Nicobar.
Earlier, Science and Technology Minister Kapil Sibal said there was no indication of a rise in the water level around the islands but added that the government was keeping a "close watch".
A seismologist from the National Geophysical Research Institute in Hyderabad said there was no chance of a tsunami hitting the islands or the mainland coast.
"There is no chance of a tsunami hitting our coastline because of this earthquake," he said. "The possibility is ruled out."
Around 400,000 people live in the Andaman and Nicobar islands, located 1,200 km (750 miles) off India's eastern coast.
Local weather officials in Tamil Nadu on the east coast -- which was also hit by the December 2004 tsunami -- said they had not issued a warning.
India is currently setting up a tsunami warning system.