The White House said Thursday that Gaza ceasefire talks in Qatar involving top US officials had a "promising start" but that it did not expect to close a deal immediately.

"Today is a promising start," National Security Council spokesman John Kirby told reporters, who confirmed that the talks opened in Doha involving CIA Director William Burns.

"There remains a lot of work to do. Given the complexity of the agreement, we do not anticipate coming out of these talks today with a deal," he said.

Kirby said he expected the talks to continue on Friday.

"This is vital work. Remaining obstacles can be overcome, and we must bring this process to a close," he said.

"We need to see the hostages released, relief for Palestinian civilians in Gaza, security for Israel and lower tensions in the region, and we need to see those things as soon as possible."