UNITED NATIONS — On the eve of President Bush’s trip to the Middle East, the Hezbollah leader, Sheik Hassan Nasrallah, stirred anti-American and anti-Palestinian Arab sentiments in Lebanon to bolster a political campaign to strengthen the country’s pro-Syrian and pro-Iranian factions.

Mr. Bush will travel next week to Israel, the West Bank, Kuwait, Bahrain, the United Arab Emirates, Saudi Arabia, and Egypt. Although Lebanon is not part of his official itinerary, he will “encourage support” for the government of Prime Minister Siniora, the American national security adviser, Stephen Hadley, told reporters yesterday.

In Beirut, Mr. Siniora responded yesterday for the first time to Sheik Nasrallah, whose nationally televised speech Wednesday dampened any hope of soon resolving the impasse over the choice of president. In the speech, he alleged that America has a plan — to be implemented by Mr. Siniora’s government — to turn Palestinian Arabs who have resided in the country for half a century into permanent citizens.

America is attempting to establish “a pro-U.S. government in Lebanon, which would facilitate the building of U.S. military bases and follow the orders of the U.S. administration,” Sheik Nasrallah said in the speech, adding America wants is to “forever abolish the spirit and culture of resistance in Lebanon.” One way to do that, he said, was to settle the Palestinian Arabs in Lebanon as part of a larger solution to the regional problem — “not for humanitarian reasons of course but to jeopardize the Palestinian cause and the right of Palestinians to return to their homeland.”

“Why do we use the issue of normalizing the Palestinians to provoke unrest, while all political parties agree on opposing this scheme?” Mr. Siniora responded yesterday, according to the Lebanese Web site Naharnet.

According to the U.N. agency that cares for descendants of Arabs who had fled or were chased out of British-mandated Palestine in 1948, there are currently 409,714 Palestinian Arabs registered as refugees in Lebanon, or 10% of the country’s population. Although Israeli and Palestinian Arab negotiators have reached tacit agreements to allow for settling many of the decedents of the 1948 refugees in their current countries of residence, all of Lebanon’s politicians have long resisted any such settlement. When the Arab League adopted the so-called Saudi peace plan at a Beirut 2002 summit, Lebanon insisted the plan would include a clause assuring that refugees would not gain local legal status.

In his Wednesday speech, Sheik Nasrallah said the American plan to control Lebanon – including through settling the Palestinian Arabs there — could only be foiled by giving his supporters a veto power over decisions taken by the next government. As part of the campaign to gain further power in Beirut politics, the Shiite speaker of Parliament, Nabih Berri, has postponed a dozen attempts to convene the legislature for a vote on a new president. No government can be constitutionally formed before a president is picked.