|PIC1|Pope Benedict, on his first papal visit to the United States, meets President George W Bush at the White House and US Roman Catholic bishops at a Washington basilica on Wednesday, his 81st birthday.

More than 9,000 people are expected to attend the White House ceremony, making it "one of the largest arrival ceremonies ever held at the White House", Bush's spokeswoman Dana Perino said.

The meeting with US bishops at the National Shrine of the Immaculate Conception will include an address in which the Pope is expected to discuss the scandal of sexual abuse of children by priests, which he said had left him "deeply ashamed".

The scandal, which broke in 2002 and forced US dioceses to pay damage settlements amounting to $2 billion, has tarnished the Church's image and created considerable dissatisfaction among American Catholics.

Pope Benedict and Bush both oppose abortion and embryonic stem cell research, but differ on questions such as the Iraq war.

The Vatican opposed the US-led invasion of Iraq in 2003 but now see US troops as a stabilising force who help protect threatened Christian minorities.

"I really don't think that the president is planning to spend a lot of time talking about the issues of Iraq with the Pope," Perino said. "The root issue of terrorism and extremism is something that they will talk about."

Pope Benedict told reporters during his trans-Atlantic flight he would ask Bush to boost development aid to poor countries so their citizens would not need to migrate.

"The fundamental solution is that there will be no need to emigrate, that there will be enough jobs and a sufficient social fabric so no one has to emigrate any more," he said in English.

"The United States has to help these countries develop. It is in the interest of everyone, not only these countries but of the world and particularly of the United States."

Perino said the two would discuss ways of protecting human rights, combating extremist ideology especially in the Muslim world and building interfaith dialogue and religious freedom.

She singled out Africa and Lebanon as regions of concern.

Pope Benedict is expected to deliver an upbeat message to US bishops despite the sexual abuse scandal. In his in-flight remarks, he expressed respect for the role of religion in public life and said the US Church was a force for good.

"Amid all the painful things, let us not forget how much real humanity there is, how many positive acts there are," he said.

The papal visit and his rides in the popemobile through Washington are expected to cause traffic chaos in the US capital, where security is tight.

Bush will host a birthday party in Pope Benedict's honour at the White House on Wednesday evening, but the Pope - who rarely attends big social functions - will not attend. Most of the guests will be US Catholic leaders.