US Secretary of state John Kerry is warning Israeli and Palestinian leaders that they must "lead" as Middle East peace talks are again on the brink of collapsing after both sides took steps Washington slammed as "unhelpful".

Although Israeli and Palestinian negotiators met US diplomats in Jerusalem to try to push ahead with talks, Israel has vowed to keep expanding settlements in the Arab-occupied East Jerusalem, and the Palestinian president Mahmoud Abbas made a surprise bid to sign more than a dozen international conventions.

White House deputy spokesman Josh Earnest said Washington is "disappointed by the unhelpful, unilateral actions that both parties have taken in recent days".

He added that Kerry was "in close touch with our negotiating team, which remains on the ground in the region to continue discussions with the parties".

The US secretary, who has made frantic efforts in recent weeks to keep the peace talks from collapsing, said there is a limit to what the Obama administration can do and told Israeli and Palestinian counterparts that they must act now.

Blaming each other

Israel laid blame on the Palestinian side, claiming it was up to Abbas to resolve the standoff.

Hawkish foreign minister Avigdor Lieberman said Israel had done "all it could to try to reach a settlement with the Palestinians, and now the ball is in their court."

However, a senior Palestinian official said the talks had become "negotiating about negotiating".

The stand-off was caused by Israel's refusal to carry out a pledged release of 26 Palestinian prisoners, prompting the Palestinians to apply to join 15 international conventions, including the Geneva Conventions.

The move is aimed at bolstering their claims to statehood and challenging Israel's occupation of the West Bank before the UN and other organisations.

Palestinians hope to appeal to the International Criminal Court and file formal complaints against Israel for continued occupation of territory seized in 1967. Israeli settlements are illegal according to international law.

Law professor Robbie Sabel, a former legal adviser to the Israeli Foreign Ministry, described Abbas's signature on the conventions as "merely symbolic".

'Crisis mode'

"We're in predictable crisis mode," said Jon Alterman, a Middle East expert at the Center for Strategic and International Studies in Washington. "The question is whether this is a serious hiccup that gets us to something significant or this is a serious hiccup that says the whole thing was a farce all along."

However another senior US official played down the idea that the peace process was collapsing, saying that both sides were willing to keep negotiating ahead of the 29 April deadline.