NAVAL BASE GUAM — Military drills on Guam in which four countries were to practice amphibious landings and moving troops have been postponed indefinitely after a French landing craft ran aground today.

The exercises involving the U.S., U.K., France and Japan were to show support for the free passage of vessels in international waters amid concerns China may restrict access to the South China Sea.

The French catamaran ran aground just offshore but didn’t hit coral or spill any fuel, said Jeff Landis, a spokesman for Naval Base Guam. No one was injured. Friday’s landing was meant to be a rehearsal for a drill at Tinian island on Saturday, Landis said.

U.S. Navy Capt. Jeff Grimes, chief of staff for Joint Region Marianas, said the authorities involved were working to assess the situation and didn’t know when the drills would resume. “I have directed that we stop all operations associated with this exercise until we conduct a further assessment of the situation as we gather all the facts,” Grimes said.

“NOAA in Honolulu is aware and is collecting information about the incident,” said Michael Tosatto, administrator of a National Oceanographic and Atmospheric Administration regional office.

The drills were to include amphibious landings, delivering forces by helicopter and urban patrols.

Two French ships on a four-month deployment to the Indian and Pacific oceans were to be involved. Joining were Japanese forces, U.K. helicopters and 70 U.K. troops deployed with the French amphibious assault ship FS Mistral. Parts of the exercise were to feature British helicopters taking U.S. Marines ashore from a French vessel.

China claims virtually the entire South China Sea and has tried to build islands — some with runways, radars and weapons systems — on seven mostly submerged reefs. The work is opposed by other governments that claim the atolls and by the United States, which insists on freedom of navigation in international waters.