Heckled inside the Australian parliament and jeered by protesters outside, President Bush defended the Iraq invasion and war on terror, saying Australia and the United States had to lead by example. Bush, wrapping up a six-nation Asian tour, told a joint session of parliament that Australia and the United States had a "special responsibility throughout the Pacific" to help keep peace. The American president is on a whirlwind visit to Australia to thank conservative Prime Minister John Howard for helping in the U.S.-led war on terror and in Iraq. His 20-hour visit has triggered a massive security operation in the usually sleepy capital with armed air force jets escorting him into Canberra on Wednesday night with orders to shoot any unauthorized aircraft and patrolling over the city on Thursday. Authorities took the unprecedented step of barring the public from the national parliament where Bush spoke on Thursday, backing a special security role for Australia in the Asia-Pacific region that has raised concerns among Asian neighbors. "Security in the Asia-Pacific region will always depend on the willingness of nations to take responsibility for their neighborhood, as Australia is doing," Bush told parliament. But his tagging of Australia as a regional "sheriff" and staunch defense of the Iraq war angered left-leaning Green politicians whose yells twice stopped the president's speech. "We are not a sheriff," shouted Greens leader Bob Brown who ignored an order to leave the house. The heckling did not rattle Bush who is on his first trip to Australia and will head home later on Thursday. "I love free speech," he quipped, to cheers from the house. But following Bush's speech, the parliament voted to suspend Brown and his Greens colleague Kerry Nettle from parliament for 24 hours, which will bar them on Friday when Chinese President Hu Jintao is due to address the parliament during a three-day trip. **TEMPERS FLARED*** Security guards removed one person from the chamber packed with well-known Australians, including TV-celebrity Crocodile Hunter Steve Irwin in his trademark khaki shorts and tennis star Lleyton Hewitt. The 18-year-old son of Mamdouh Habib, one of two Australians held at a U.S. military prison in Cuba for two years without charge after the Afghan invasion, was dragged out, arms pinned behind his back, after yelling: "Hey Bush, what about my Dad?" While tempers flared inside the hill-top parliament, a crowd of up to 2,000 protesters outside chanted anti-U.S. slogans and waved banners reading: "Yankee Go Home" and "U.S. Sucks." Through the crowd weaved an Osama bin Laden lookalike, carrying a placard reading "Come and Get Me" and two activists dressed as Saddam Hussein and Bush holding hands. About 1,000 police and security specialists were deployed in Canberra on Thursday to guard against any incident while Bush and his 650-person entourage were in town. It's the first U.S. presidential visit to Australia since Bill Clinton came in 1996. Howard's drive to tighten ties with the United States during his seven years in power has sparked some criticism within Asia. But Howard, who visited Bush at his Texas ranch in May, said the relationship would only become tighter, with the two nations hoping to complete a free trade agreement by the end of the year. "The significance of America to Australia will grow as the years go by, it will not diminish," he told the parliament. **PHOTO CAPTION*** Australia's Green Party senators Bob Brown, second right, and Kerry Nettle, right, are warned by a Parliament official after they heckled a speech by U.S. President George W. Bush to Australia's Parliament in Canberra, Thursday, Oct. 23, 2003. (AP Photo/Charles Dharapak)