Singapore has sent more military planes and ships to help in the six-country search for the Malaysia Airlines (MAS) plane that went missing on Saturday.
Two military transport planes, a naval helicopter, two warships and a submarine support and rescue vessel are currently involved in the search, said the Ministry of Defence in a statement on Sunday.
These exclude the first military transport plane that had been deployed on Saturday which has since returned, the ministry added.
In a post on its Facebook page at about 9am on Sunday, the Republic of Singapore Navy (RSN) said that its missile corvette, frigate and Sikorsky S-70B Seahawk naval helicopter joined in the search for MAS flight MH370 at 2am on Sunday.
The naval helicopter - which can drop sonar underwater - is on board the RSS Steadfast, one of the navy's Formidable class of frigates - its most advanced warships that are designed for stealth, speed and manoeuvrability.
The RSS Vigour belongs to its Victory class of missile corvettes, which are fast attack vessels with search capabilities that form what the navy calls "the backbone of the RSN's strike capability".
The RSN added that its submarine support and rescue vessel, the MV Swift Rescue, which had been preparing for the operation through the night, joined in later on Sunday.
The submarine support and rescue vessel is equipped to search underwater and has divers on board.
In a tweet on Sunday morning, the Singapore Army wished them success.
Earlier, on Saturday, the first Republic of Singapore Air Force (RSAF) C-130 aircraft took off at noon to assist in the search, which the RSAF, Singapore Rescue Co-ordination Centre and the Civil Aviation Authority of Singapore are helping to coordinate.
It returned on Saturday night, and two other C-130 planes have since taken its place, the ministry said.
Singapore Defence Minister Ng Eng Hen called his counterpart, Malaysia Defence Minister Hishammuddin Hussein, on Saturday night to convey Singapore's sympathies and offer assistance.
On top of the military transport plane, he also offered the use of the submarine support vessel, which Mr Hishamuddin, who is also Acting Transport Minister, accepted.
On Saturday, both Singapore's Chief of Navy, Rear-Admiral Ng Chee Peng, and Chief of Air Force, Major-General Hoo Cher Mou, spoke to their counterparts, the Chief of the Royal Malaysian Navy, Admiral Tan Sri Abdul Aziz Haji Jaafar, and the Chief of the Royal Malaysian Air Force, General Tan Sri Dato Sri Rodzali Daud, to coordinate the details of the Singapore Armed Forces' assistance and offer additional assistance if required.
Malaysia, Vietnam, the Philippines, China and the United States are also involved in the search for the missing plane.
The Boeing 777-200 aircraft, which was bound for Beijing from Kuala Lumpur, took off just after midnight on Saturday, and lost radar contact 50 minutes later.
It was carrying 227 passengers and 12 crew members from 14 countries and Taiwan. There were no Singaporeans on board.
Two giant oil slicks, consistent with the sort that would be left by fuel from a crashed jet, were spotted in the sea off southern Vietnam on Saturday night, but no debris has been found.