Most countries in the region opted for caution after the White House claimed victory for the incumbent and challenger John Kerry conceded defeat.
The Palestinian Authority's envoy to France admitted that veteran leader Yasir Arafat, who is being treated in Paris for a serious but undiagnosed illness, was "worried".
Arafat "hopes the second mandate will be different" if Bush is confirmed the winner of Tuesday's election, Laila Shahid said.
Echoing a generally negative Palestinian stand towards Bush, deputy parliament speaker Hasan Khraishah said that "neither Bush nor Kerry spoke about the Palestinian question during their campaign".
"Bush has only served to isolate the Palestinian leadership and block the peace process," he said.
In a region rife with anti-US sentiment, Kerry was seen by many Arabs as the candidate with less aggressive policies, or at least as the sole alternative to a man whose unpopularity is matched only by Israeli premier Ariel Sharon.
However, polls revealed some Arabs wanted Bush to win a second term in the hope that the Republican's Middle East policies would backfire on the United States.
In Iran, where hatred of the "Great Satan" is deeply entrenched, thousands of demonstrators chanting "Death to America" marked the 25th anniversary of the US hostage crisis at the former American embassy in Tehran.
"If Bush is re-elected or not... we will continue to resist with determination and foil the US plots," said a female member of a Islamic volunteer brigade.
Arabs overwhelmingly opposed
the US-led invasion of Iraq
And Muhammad Muhammadi, parliament's foreign affairs committee deputy speaker, warned that America was headed for "international and economic ruin unless Bush is more careful in his second term", the student news agency ISNA said.
On the other hand, Israel and the US-backed interim leaders of Iraq were confident a second term for Bush would signal more of the same policies.
Before the election result was announced, Iraqi interim Prime Minister Iyad Allawi was upbeat.
"Whoever is the winner will be our friend. The United States has liberated us from a dictator and a very long period of war and agony," Allawi said in an Italian newspaper interview published on Wednesday.
An inexperienced new team under Senator Kerry would be worse than maintaining the status quo, officials and politicians in Baghdad said.
"We know that Bush has an overall vision for Iraq, he overthrew Saddam Hussein and liberated the country and I think he wants to see the job done," said Muwaffaq al-Rubaye, a special advisor to the interim government.
The re-election of the man who decided to invade Iraq in March 2003 comes as US-Iraqi forces are braced for a military assault on the Iraqi city of Falluja.
The Sharon administration is the
US's closest ally in the region
Meanwhile, buoyed by unequivocal pre-election messages of support from both candidates, Israel was confident it would preserve its special relationship with Washington.
Foreign Minister Silvan Shalom said he did not expect Israel to come under any heightened US pressure over the dormant peace process.
"So far we have cooperated with all American administrations and we will continue to do so. I don't think pressure will be necessary, Israel wants to advance on the road to peace," he said.