ROME, Italy (CNN) -- U.S. President George W. Bush's farewell tour of Europe took him to Rome on Thursday, where he met with his friend and ally, Italian Prime Minister Silvio Berlusconi.
Iran and Afghanistan were high on the agenda but at a news conference Bush was also asked about a U.S. Supreme Court blow to his administration's war on terror policies.
Bush said he disagreed with the ruling that Guantanamo Bay detainees have the right to challenge their detention in federal courts, but he would abide by it.
"Congress and the administration worked very carefully on a piece of legislation that set the appropriate procedures in place as to how to deal with the detainees," he said. Watch analysis of the decision »
"We'll study this opinion, and we'll do so with this in mind to determine whether or not additional legislation might be appropriate so that we can safely say, truly say to the American people. 'We are doing everything we can to protect you.'" Watch more from Bush on the ruling »
During a joint news conference with Berlusconi, Bush said Iran must give up its ambitions for nuclear power for the sake of peace or else face continued sanctions and isolation.
Bush insisted there was still a diplomatic way to solve the Iranian nuclear issue but that "the choice is up to (Iran)," saying that it's the Iranian people who are suffering and "whose lives could be more hopeful."
Bush said that all countries have a right to seek nuclear energy but only for civilian use. The U.S., and some other Western nations, believe Iran's program is a mask to develop nuclear weapons.
Berlusconi, known for his flamboyant style, has remained one of Bush's staunchest allies in Europe over the years. The Italian began his second term as prime minister in 2001, months after Bush entered the White House and shortly before the September 11 attacks.
Berlusconi has remained one of Bush's staunchest allies in Europe over the years.
In exchange for easing fighting restrictions on its soldiers deployed in Afghanistan, as requested by NATO and the United States, Italy wants a greater role in dealing with Iran's nuclear threat.
Berlusconi's support for Bush has been important, especially where the issue of troops for Iraq and Afghanistan have been concerned. Italy initially contributed troops to the war in Iraq but no longer has troops in the country; it still takes part in the NATO mission in Afghanistan.
Iraq could have also been one of the things that cost Berlusconi reelection in 2006. Polls show a majority of Italians oppose the war, and voters clearly didn't believe Berlusconi when he said he tried to convince the U.S. president not to invade Iraq. But Berlusconi still won reelection in April this year.
Bush plans to meet with Pope Benedict XVI at the Vatican on Friday before traveling on to France and Britain.
Leading up to his afternoon meeting with Berlusconi, Bush held a roundtable discussion Thursday morning with Italian entrepreneurs who worked or will work at U.S. companies in Silicon Valley in California. He then met with Italian President Giorgio Napolitano at Rome's Quirinale Palace. On Friday, Bush planned to meet with Pope Benedict XVI at the Vatican before traveling on to France and Britain.