JERUSALEM — Plans for a Palestinian government of national unity were put on hold yesterday as its two main factions wrangled over the details of the power-sharing agreement.

The militant Islamist party Hamas and the largely secular Fatah movement of Palestinian President Abbas had agreed to joint rule, which they hoped would bring an end to the international embargo on the current Hamas-ruled administration.

But a spokesman for Mr. Abbas said the unity government was on hold after Hamas — which does not recognize the state of Israel’s right to exist — refused to acknowledge previous Palestinian agreements with the Jewish state.

“All of the president’s efforts have been disrupted by a number of statements from leaders of Hamas announcing the lack of readiness of any government formed by Hamas to respect the obligations and agreements of the Palestinian Liberation Organization,” an aide to Mr. Abbas, Nabil Amr, said.

As a result, the president had decided on “the freezing of efforts to form the national unity government,” he said.

The Palestine Liberation Organization is the Palestinian Arab umbrella group that has historically been responsible for negotiating with Israel.

The delay underscored the difficulty Mr. Abbas was having in trying to force Hamas to soften its anti-Israel ideology, a move that would pave the way for an end to the international sanctions that have crippled the Palestinian economy.

Some Palestinian officials wondered whether the two sides would be able to bridge their differences.

Hamas downplayed the differences, however, with a Hamas government spokesman, Ghazi Hamad, saying it was no longer possible to turn back on the proposed unity government.

“The idea of a national unity government has become an idea that all parties are bound to,” he said.