Tsunami warnings in across all areas of the Indian Ocean have been lifted after an earthquake measuring 8.7 on the Richter Scale struck off the coast of Indonesia.
A report issued by the Pacific Warning Centre said: "A significant tsunami was generated by this earthquake. However sea level readings now indicate the threat has diminished or is over for most areas. Therefore the tsunami watch issued by this centre is now cancelled.
"For any affected areas - where no major waves have occurred for at least two hours after the estimated arrival time or damaging waves have not occurred for at least two hour - then local authorities can assume the threat has passed."
It added: "Danger to boats and coastal structures can continue for several hours due to rapid currents. As local conditions can cause a wide variation in tsunami wave action the all-clear determination must be made by local authorities."
The British Foreign Office advised travelers to monitor local media for advice and to call home to let their families know they are safe.
Banda Aceh was near the epicentre of the devastating 2004 quake that triggered a tsunami across the Indian Ocean, which killed 170,000 people.
Thailand's national disaster prevention centre had earlier issued a tsunami warning for six southern provinces along the Andaman coast.
People in the popular tourist destinations of Phuket, Krabi, Ranong, Phangnga, Trang and Satun had been told to move to higher ground because of a possible tsunami.
Tremors were felt as far away as the Thai capital, Bangkok, and in southern India, residents said.
In India Yahoo readers reported feeling aftershocks in Hyderabad and Orissa, while Metro trains were shut down as a precautionary measure in Bangalore.
Chennai's Marina Beach-front was also evacuated in anticipation of big waves.
India has now withdrawn its national tsunami alert.
"Thankfully, the danger has passed," a scientist at the Indian tsunami warning centre said.
S.R. Jayasekera, a deputy director of the Meteorological Department of Sri Lanka, said: "We have lifted the warning. People now can go back to their homes. But we are still advising not to go to sea as there has been some high tides in some areas washing away some boats,"
Kenya and Tanzania had also announced tsunami warnings along their Indian Ocean coastlines.
The earthquake hit 308 miles (500 km) southwest of the city of Banda Aceh, on the northern tip of Indonesia's Sumatra island, according to the U.S. Geological survey.
Sirens warned of the danger in Aceh as people gathered on high ground.
But Indonesian President Susilo Bambang Yudhoyono said there were no signs of a disaster.
"There is no tsunami threat although we are on alert," he said at a joint news conference in Jakarta with visiting British Prime Minister David Cameron, who said Britain was standing ready to help if needed.