A joint US-South Korean military exercise that had been expected this month will most likely take place in July, though a date has yet to be set, the Pentagon said on Monday.
The United States first announced plans in May to hold a joint anti-submarine drill with the South "in the near future" but the timeline has repeatedly slipped amid concerns about increasing tensions with North Korea.
A South Korean warship was sunk off the peninsula's west coast in March, killing 46 sailors.
Seoul and the United States have blamed North Korea for sinking the Cheonan with a torpedo fired from a submarine, a charge the North denies.
"I still don't have a date for you. The details are still being worked out," Pentagon spokesman Bryan Whitman told reporters when asked about the planned exercise.
"We're still committed to further bilateral exercises with the Republic of South Korea," he added.
The Pentagon had initially said it expected the joint exercise to take place in late June.
Whitman said July now appeared more likely but was noncommittal about the timing. North Korea has said that the planned exercises were part of a "dangerous scheme to disturb the peace".
China has said it was worried the show of naval force could unsettle the region further. China has resisted calls from Seoul, Washington and Tokyo to join in condemning Pyongyang over the Cheonan sinking, instead saying it needed to assess the competing claims.