US President George W. Bush, denounced by tens of thousands of anti-American protesters on the streets of Rome, defended his humanitarian record on Saturday to Pope Benedict XVI, who expressed concern about "the worrisome situation in Iraq." Bush also sought to shore up relations with Premier Romano Prodi, whose center-left government has been heavily critical of US policies. While Prodi has withdrawn Italian forces from Iraq, Bush thanked him for Italy's leadership in supporting the fragile western-backed government in Lebanon and its commitment of 2,000 troops for NATO's mission in Afghanistan. Relations with Italy are "pretty darn solid," Bush said. Prodi agreed. "We basically agree on how the future of the world should look, should be," the Italian leader said. The president went to the Vatican for his first meeting with the pope, who has lamented the "continual slaughter" in Iraq and concluded that "nothing positive comes from Iraq." The pope asked Bush about his talks in Germany with Russian President Vladimir Putin at a time of deep strain between Moscow and Washington. "The dialogue with Putin was also good?" the pope asked. "I'll tell you in a minute," Bush said, mindful of the presence of reporters and television cameras during the photo opportunity. They both laughed. "I was talking to a very smart, loving man," Bush said later of his discussion with the pope. "I was in awe and it was a moving experience." Highly unpopular in Italy and across Europe, the president made a point about US efforts to fight disease and poverty in Africa. Bush recalled that he had asked Congress to double the commitment for fighting AIDS in Africa, from $15 billion to $30 billion. Tens of thousands of anti-globalization and far-left activists marched peacefully through the capital's ancient center to protest Bush's visit. Thousands of police were deployed round the Colosseum, the downtown Piazza Venezia and other sites. As the protests were concluding, riot police used tear gas on small groups who threw bottles and donned masks in defiance of a police order. More than an hour into the clashes, police charged the demonstrators, pursuing them down alleyways to break up the crowd as helicopters circled overhead. News agency ANSA said six people were taken into custody. White House aides shrugged off the protests, calling them democracy in action; Bush apologized for disrupting traffic as his motorcade moved through Rome under heavy security. The president received a splashy Vatican welcome. Television cameras recorded his every move as Bush walked through marbled Vatican halls to the pope's private library. The president and pope talked for 35 minutes. Afterward, Laura Bush, wearing a black mantilla head covering, joined the president and pope. The president said the pope expressed concern that the Muslim majority in Iraq was intolerant of Christians. A Vatican statement said Bush, in talks with the pope and the Vatican's No. 2 official, Cardinal Tarcisio Bertone, discussed the "worrisome situation in Iraq" and the "critical conditions in which the Christian communities (in Iraq) are found," the statement said. Bush said the United States is pressing Iraq - torn by sectarian violence - to live by a constitution "that would honor people from different walks of life and different attitudes." He said there was no discussion whether Iraq was a "just war." Bush, who was ill on Friday, was still suffering some effects of a stomach problem. Spokeswoman Dana Perino said the president was "not 100 percent " but that "it's not slowing him down a bit." As previously scheduled, Bush had nothing on his schedule Saturday evening. He departs early Sunday to visit Albania and Bulgaria. The president's trip came at an awkward time. Just hours before Bush's arrival Friday, the first trial involving the CIA's extraordinary rendition program opened in a Milan courtroom. There are 26 Americans on trial in absentia for the abduction of an Egyptian cleric. Prodi said they did not talk about the case. "We have very clear-cut rules that we follow and we, therefore, enforce our rules." While the issue has strained relations, Prodi said he was confident it would not affect US-Italian friendship. Bush met privately with former Italian Prime Minister Silvio Berlusconi, a like-minded conservative and strong ally of the president's. "He is the opposition leader and he is a friend," Bush said, explaining his decision to visit with Berlusconi. Bush said Prodi didn't "blame" the president for stopping to chat with his predecessor. Bush also expressed frustration about the lack of international consensus on granting Kosovo independence from Serbia. "This needs to happen," Bush said. "Now, it's time." The summit in Germany failed to produce an agreement about Kosovo after French President Nicolas Sarkozy called for a delay. Bush also visited, at the US embassy, with members of a lay Roman Catholic organization. The Sant'Egidio Community has a $25 million program, partly funded by the United States, to provide free antiretroviral drugs for HIV-positive people in 10 African countries, along with follow-up and home care. Members of Sant'Egidio said it was sometimes difficult for them to access funds, such as the president's fund for AIDS in Africa, because the money is often given to governments, not organizations. Bush suggested his administration would look into making it easier for a faith-based initiative such as Sant'Egidio to access the money.