"We have an agreement over the document," Ibrahim Abu Najah said.
Salah Zeidan, another negotiator, said a formal signing ceremony would come soon. "All political groups are prepared for a mutual cease-fire with Israel," he added.
President Mahmoud Abbas of Fatah has been trying to coax Hamas into backing the document, which was written by senior Palestinian prisoners held by Israel.
Abbas has promoted the plan as a way to reopen peace talks with Israel and end economic sanctions that have crippled the Hamas-led Palestinian government.
However, a crisis over the abduction of an Israeli soldier and opposition by the militant group Islamic Jihad overshadowed the deal.
"In today's meeting, we announced we reject some of the articles of this document and we have reservations about other articles," said Khaled al-Batch, spokesman for Islamic Jihad, which has carried out numerous attacks against Israel.
The plan calls for a Palestinian state alongside Israel, in effect recognizing Israel. It also calls on militants to limit attacks to areas captured by Israel in the 1967 Mideast War and calls for formation of a coalition Palestinian government.
Hamas and Fatah have been locked in a bloody power struggle since Hamas won legislative elections in January. Hamas controls the parliament and Cabinet. Abbas, a political moderate, was elected separately last year.
Israel has said the document is an internal Palestinian matter, but said it falls short of international demands that Hamas renounce violence and formally recognize the Jewish state.
With Hamas-linked militants holding a captured Israeli soldier, the Palestinian agreement is even less likely to reduce tensions. Israel has massed troops along its border with Gaza, promising a broad offensive into the area.
The Associated Press contributed to this report.