The president is due to meet Belgian leaders on Monday and European Union and NATO leaders on Tuesday to talk about Iran, Syria and Iraq as well as NATO's future.

More protests are expected over the coming days with environmental, human rights and peace groups, the far left, socialists and anti-globalists all planning to take to the streets.

Several hundred left-wing demonstrators gathered in the historical heart of Brussels -- home to NATO and the EU -- to criticise Bush for not signing up to the Kyoto treaty to tackle global warming and for the US-led war in Iraq.

One demonstrator carried a flag with a Nazi swastika sign woven into a US flag, while the front page of a communist weekly had an image of the famous Brussels Manneken Pis statue urinating on Bush's head. Other protesters held communist flags.

"I am protesting against Bush's visit and the fact that security is being funded by the Belgian taxpayer. That's inappropriate for such a criminal," said 25-year-old Tom, a social worker.

Outside the US embassy, several dozens of nationalist right-wing demonstrators, some of them skinheads, demanded US troops to pull out of Europe.