Australia's prime minister came under fire at home Friday over a playful salute he gave U.S. President George W. Bush at a NATO summit, which critics said seemed to suggest Australian subservience to Washington.

Australian television repeatedly broadcast videos of the gesture Thursday on the sidelines of the Bucharest summit and speculated about what it meant, while opposition lawmakers said it belittled Australia.

"We are not the 51st state of the United States of America and Mr. Rudd's salute carried a subservient connotation many Australians won't like," said Bob Brown, leader of the minor opposition Greens pary.

The salute revived memories of Southeast Asian countries, including Malaysia, accusing Australia under former Prime Minister John Howard of being too close to Bush and too willing to adopt hawkish U.S. foreign policy.

Rudd explained that he was just being friendly toward a world leader whom he had met for the first time as prime minister a week earlier in Washington.

"It was just a joke," Rudd told Australian reporters in Bucharest. "I was just saying 'hi' to the president of the United States — I was just with him the other day."

After saluting, Rudd strode through other NATO leaders to shake Bush's hand and spoke to the U.S. president while smiling.

Rudd replaced Howard as prime minister in elections last November. Rudd, a Chinese-speaking former diplomat to Beijing, has promised to follow an independent foreign policy and to withdraw 550 Australian combat troops from Iraq this year.