Ramallah, West Bank ? Mahmoud Abbas got a major boost in his increasingly bellicose showdown with Hamas on Saturday, with a U.S. diplomat saying he expects a crippling embargo to be lifted once the Palestinian president appoints a government without the Islamic militants.

But the money is unlikely to reach Gaza, now controlled by Hamas and cut off from the world.

The new Cabinet is to be sworn in today in the West Bank, where Fatah forces stormed government offices on Saturday, just three days after Hamas seized control of Gaza and Abbas dismantled the Hamas-Fatah coalition government in response.

Abbas issued a decree early today annulling a law requiring the new government to be approved by parliament, which is dominated by Hamas.

Hamas spokesman Sami Abu Zuhri said the decree was illegal.

“This escalates the crisis, and the president bears the responsibility for all the consequences of these developments,” he said.

In another boost for Abbas, Israeli Prime Minister Ehud Olmert said the new Palestinian government would create a “new opportunity” for the peace process. Olmert has long welcomed Abbas as a negotiating partner, but said Abbas’ alliance with Hamas made peacemaking virtually impossible.

“We have a new opportunity … that we haven’t had in a long time,” Olmert told reporters on board his plane shortly before taking off for a meeting at the White House.

“The situation has changed, which enables diplomatic progress … We intend to act to take advantage of this situation,” he said. “A government that is not Hamas is a partner.”

In Gaza, panicked residents stocked up, fearing growing shortages of food, fuel and other staples as the crossings of the fenced-in strip with Israel and Egypt remained closed. Hundreds of other Gazans rushed to the border crossing with Israel to try to escape Hamas rule, but found gates locked. Israeli troops briefly fired warning shots.

Senior officials of Abbas’ Fatah movement, who had fled Gaza, started reaching the West Bank. The head of Palestine TV said he had crawled for several hundred yards to evade gunfire at the Gaza-Israel crossing before making it to safety.

“Hamas has always targeted me. Once they fired shots (at) my car. And they wrote on their Web site that I am broadcasting sedition,” said Abdel Salam Abu Nada. Recently, he received an ominous text message on his cell phone saying, “Your punishment is coming.”