Minutes after the US guided-missile destroyer USS John S. McCain and Liberian-flagged merchant vessel Alnic MC collided, the Maritime and Port Authority of Singapore (MPA) received an alert on the accident in Singapore's waters.
The Singapore authorities, including the navy and air force, then launched search and rescue operations for 10 US sailors who were reported missing. Another five were injured during the collision.
Operations were continuing through the night, the MPA said in a statement last night providing updates on the efforts.
It said the Republic of Singapore Navy's (RSN) patrol vessel RSS Gallant and Singapore Police Coast Guard's (PCG) PH55 were on patrol in the vicinity when the incident happened at 5.24am, and provided help after receiving an alert at 5.30am.
At 6.45am, MPA sent three tugboats and a team of divers to the collision site in the Singapore Strait.
The Republic of Singapore Air Force (RSAF) dispatched its first Super Puma at 7.39am, after being notified by the US Navy of missing and injured crew members.
The MPA deployed its command vessel at 8am while another RSN patrol vessel, RSS Resilience, and PCG's PH53 patrol vessel both arrived at the scene at around 9am.
RSN's frigate RSS Intrepid was also deployed, followed by another Super Puma and a Chinook helicopter.
In total, some 250 personnel were deployed for the search and rescue operations. The Singapore Armed Forces deployed one frigate, two patrol vessels, two Super Pumas and one Chinook helicopter, while the PCG deployed two patrol vessels. Five sorties were carried out by 6pm yesterday.
MPA said it has also been issuing hourly navigational broadcasts to advise passing vessels of the incident and request them to keep a lookout for persons in the water.
One of the RSAF Super Pumas transferred four of the injured from the vessel at sea to Singapore General Hospital, while the fifth was taken via an ambulance to the hospital after the US destroyer berthed at Changi Naval Base.
The Alnic MC is berthed at Singapore's eastern anchorage for inspections, said the MPA, which is investigating the incident. It added that search and rescue efforts for the 10 missing sailors would continue through the night.
MPA chief executive Andrew Tan said: "Our thoughts are with the injured and families of the US Navy crew who are currently still missing following the incident in Singapore territorial waters. The Singapore authorities will spare no effort to try to find them, and render all possible assistance to our US friends."
US Navy Secretary Richard Spencer, in a Twitter post last night, expressed his "appreciation to the Government of Singapore for their swift support and assistance during this time of need".
"The United States Navy will fully investigate the cause of this incident, and I ask all of you to keep the families of John S. McCain in your thoughts and prayers as we begin the task of answering the many questions before us," he wrote.
The Straits Times visited the vicinity of the collision site yesterday and saw busy shipping activity, with vessels of various sizes ranging from tankers to smaller craft travelling at different speeds from all directions. Visibility at night was poor, making it hard to see far, with some of the bigger ships poorly lit.
Malaysia, claiming that the collision took place within its territory, said it had launched a search and rescue operation at 8.45am, after being notified at 8am by the Royal Malaysian Navy's KD Handalan, which in turn received an alert from USS John S. McCain at 7.25am.
Malaysian Maritime Enforcement Agency director-general Zulkifli Abu Bakar told a press conference yesterday that it immediately deployed four vessels and also a helicopter at 11.30am, and that the Indonesian Navy was sending two vessels, KRI Parang and Cucuk.