WASHINGTON - The United States will pledge about $500 million for the moderate-led Palestinian government in the West Bank when Arab, European and other nations meet next week, U.S. officials said yesterday.

The money would go toward a goal of $5.6 billion that former British Prime Minister Tony Blair hopes to raise to rescue the tattered Palestinian economy and reinforce institutions that would become the backbone of any eventual independent Palestinian state.

Secretary of State Condoleezza Rice will deliver the pledge at a conference Blair has called for Monday in Paris, said the officials, who spoke on condition of anonymity because the precise amount had not yet been determined. The money must still be approved by Congress.

Some members of Congress are worried that money spent to strengthen the West Bank government could end up benefiting a rival radical-led government in the separate Palestinian territory of the Gaza Strip. Rice will meet tomorrow with Palestinian Prime Minister Salam Fayyad to discuss the pledge.

In the Mideast yesterday, Hamas gunmen who control the Gaza Strip burst into the home of a top Fatah official in Gaza and arrested him, relatives said. He was the most senior Fatah politician to be detained since Hamas forces overtook the territory in June.

Later in the day, three people were killed in an unexplained explosion at a funeral in Gaza City. Witnesses said a man carrying explosives in a jacket accidentally detonated them, while Hamas security said a member of the procession threw a pipe bomb.

Omar Al-Ghoul, arrested by Hamas for "illegal activities," had been spending much of his time in the West Bank after Hamas violently seized control of Gaza in June. He arrived in Gaza on Thursday.

Ghoul is an adviser to Fayyad, whose moderate West Bank government was formed after Hamas' takeover of Gaza. Ghoul is considered a harsh critic of Hamas and frequently attacks the fundamentalists in his newspaper column.

The West Bank government accused Hamas of throwing a bomb at the funeral procession and immediately declared today a national "mourning day." Fatah officials said in a statement that the bombing was a "continuation of Hamas crimes since its coup."

Hamas security officials denied their forces were involved.