SINGAPORE (AP) — An oil tanker and a dredger collided in Singapore waters Wednesday, capsizing the dredger and leaving two dead and three crew members missing, authorities said.

Divers recovered the two bodies from the partially submerged dredger, the Maritime and Port Authority of Singapore said. Seven of its crew members were rescued by the police coast guard and the search continued for the three missing.

Five aircraft and 22 vessels from Singapore were deployed to support the operations on the Dominican dredger JBB De Rong 19, which was moved to near Pulau Senang, a small island south of the main island of the Singapore city-state. The maritime authority has told ships to look out for the missing crew and to navigate with caution near the collision site.

The 26 crew members on the Indonesian oil tanker Kartika Segara were not hurt. The tanker reportedly suffered damage to her starboard bow, but the authority said there was no spill. Indonesia also sent five vessels to assist with the search and rescue.

The collision occurred about 1.7 nautical miles, or just over 3 kilometers from Sisters’ Island. The dredger was transiting in a westbound shipping lane as it was entering Singapore, while the tanker was joining an eastbound lane to depart when they collided at 12:40 a.m., the authority said. An investigation was ongoing.

The shipping lanes around Singapore are among the world’s busiest and its navigational challenges include a narrow strait, frequently limited visibility and thousands of vessels sailing through daily.

In August, the USS John S. McCain and an oil tanker collided off Singapore, killing 10 U.S. Navy sailors. The commander of the Japan-based U.S. 7th Fleet was replaced and a ship-by-ship review was ordered in the Navy following the collision. The cause of that collision is still under investigation.