Palestinian leaders say a US envoy's comments on Israel having the right to annex at least parts of the occupied West Bank show "extremists" are involved in White House policy on the issue.

In a statement late Saturday in response to US Ambassador to Israel David Friedman's comments in a New York Times interview, a Palestinian government spokesperson said some leading US policy on the issue were "extremists" lacking in "political maturity."

The Palestinian foreign ministry said it was looking into filing a complaint with the International Criminal Court on the issue.

Palestine Liberation Organization Secretary-General Saeb Erekat on Twitter called Friedman an "extreme ambassador of the settlers." "Their vision is about annexation of occupied territory, a war crime under international law," he said.

Erekat also renewed a Palestinian call for countries to boycott a June 25-26 conference in Bahrain to discuss economic aspects of a peace deal the White House has been working on.

In the interview published Saturday, Friedman said that some degree of annexation of the West Bank would be legitimate.

"Under certain circumstances, I think Israel has the right to retain some, but unlikely all, of the West Bank," he said.

Israel occupied the West Bank in the 1967 Six-Day War and its construction of settlements there is viewed as a ­major stumbling block to peace as they are built on land the Palestinians see as part of their future state.

Friedman has in the past been a supporter of Israeli settlements as has the family of Jared Kushner, US President Donald Trump's son-in-law and adviser leading efforts to put together the peace deal.

Israeli Prime Minister Benjamin Netanyahu pledged ahead of April elections to begin annexing West Bank settlements.

More than 600,000 Jewish settlers now live in the West Bank and annexed east Jerusalem among some 3 million Palestinians.