After having discreetly vouched for Obama since the party race to the White House began last year, his speech – just hours after he won his party's backing on Wednesday – has prompted second thoughts about what changes the African-American could bring to Washington's Middle East foreign policy.

Millions of Arabs were able to watch the address to the powerful American-Israeli Public Affairs Committee (AIPAC), which was aired live on some Arab television networks, serving as a "rude awakening" that the United States, regardless of its leadership, would continue to favor Israel at the expense of Palestinian and Arab rights.

Arab governments usually remain silent during U.S. elections, officially saying the polls are an internal American affair, but this year they are closely observing and privately taking sides according to foreign policy campaign pledges.

Analysts say that with a strong American political and military presence in the region and being the world's sole superpower, the turbulent Middle East is directly affected by the presidential elections and whoever ends up in the White House.

Obama's campaign pledge to fully support Israel was generally understood as a way to win over Jewish votes, but his remark that "Jerusalem will remain the capital of Israel, and it must remain undivided" has provoked Palestinian anger and concern.

Adding to the concern was the timing of his comment, which falls on the anniversary of the June 5, 1967 war and Israel's occupation of the West Bank, including East Jerusalem, and the Gaza Strip.

The two main rival Palestinian factions, nationalist Fatah that rules the West Bank and Islamist Hamas that controls Gaza, united in condemning the candidate's vow to AIPAC.

Palestinian President Mahmoud Abbas said Obama's Jerusalem statement was "totally rejected. The whole world knows that East Jerusalem, holy Jerusalem, was occupied in 1967 and we will not accept a Palestinian state without having [East] Jerusalem as the capital of a Palestinian state."

Abbas' aide and senior peace negotiator Saeb Erekat responded by saying that Obama "has closed all doors to peace."

The future of Jerusalem is one of the tough final status issues being negotiated between the Palestinians and Israelis, and the occupation and annexation of the eastern part have not been recognized by the international community, including the United States.

The U.S. and other embassies remain in Tel Aviv, resisting Israeli calls to move to Jerusalem.

Some Palestinian officials privately said they hoped that Obama's campaign promise was just a way to win over the pro-Israeli lobby in Washington, noting that previous presidential candidates had vowed to move the U.S. embassy from Tel Aviv to Jerusalem – an action that would recognize and help legitimize Israel's claim over the whole city and constitute a shift in traditional U.S. policy.

But once in the Oval Office, the promise was never fulfilled, perhaps to avert damaging relations with Washington's Arab and Muslim allies, who regard Jerusalem's Muslim sites as among the holiest.

Erekat told reporters: "We reject the positions of Barack Obama because they are in contradiction with the traditional positions of the United States, which considers East Jerusalem under occupation."

Hamas, which ousted the Fatah-led Palestinian Authority from Gaza last June, has now changed its mind about Obama after Hamas aide Ahmed Yousef was widely quoted as saying in April that "we like Mr. Obama. We hope he will win the election."

Obama, whom many Arabs and Muslims had hoped his African background and Muslim father would make him more sympathetic to their causes, came under fire by his Republican opponent John McCain, who said Hamas would welcome an Obama presidency.

Hamas spokesman Sami Abu Zuhri said his group, "does not differentiate between the two presidential candidates, Obama and McCain, because their policies regarding the Arab-Israeli conflict are the same and are hostile to us…. Obama's comments have confirmed there will be no change in the U.S. administration's policy."

Arab commentators also blasted what they called Obama's "appeasement" speech, saying while the Jewish votes and the pro-Israeli lobby's strength were important in U.S. elections, his remarks on the Middle East conflict were not very different from U.S. President George W. Bush's policies, and risks harming U.S. relations with dozens of Muslim countries.

"This cheap way of throwing himself at the feet of this lobby harms American interests … and encourages violence and terrorism by giving justification to extremist groups, such as al-Qaida," said Al-Quds al-Arabi's editorial Thursday, which added that foreign policy was for the first time an important element in U.S. elections.

"Obama is gambling with his image and the widespread hopes that many had placed on him to change the face of America, its relations with the world, and getting out of its economic crises stemming from its failed and immoral wars in Iraq and Afghanistan," the pan-Arab independent Palestinian-owned daily wrote.