The United States will veto a U.N. Security Council resolution for a ceasefire in Israel's war in Gaza if it is brought to a vote in its current form, a senior U.S. official said on Wednesday, accusing council members of cynically rejecting attempts at reaching a compromise.

The 15-member council is expected to vote on draft resolution put forward by its 10 non-permanent members in a meeting beginning at 10 a.m. EDT (1500 GMT) calling for an "immediate, unconditional and permanent ceasefire" and separately demand the release of hostages.

The American official, who briefed reporters on condition of anonymity, said the U.S. would only support a resolution that explicitly calls for the immediate release of hostages as part of a ceasefire.

"As we stated many times before, we just can't support an unconditional ceasefire that does not call for the immediate release of hostages," the official said.

Israel's 13-month campaign in Gaza has killed nearly 44,000 people and displaced nearly all the enclave's population at least once. It was launched in response to an attack by Hamas-led fighters who killed 1,200 people and captured more than 250 hostages in Israel on Oct. 7, 2023.

Ahead of a potential vote on a ceasefire resolution on Wednesday, Britain put forward new language that the U.S. would have supported as a compromise, but that was rejected, the U.S. official said.

Some of the council's 10 elected members (E10) were more interested in bringing about a U.S. veto than compromising on the resolution, the official said, accusing Russia and China of encouraging those members.

"China kept demanding 'stronger language' and Russia appeared to be pulling strings with various (elected) 10 members," the official said. "This really does undercut the narrative that this was an organic reflection of the E10 and there's some sense that some E10 members regret that those responsible for the drafting allowed the process to be manipulated for what we consider to be cynical purposes."