Lebanese demonstrators have set the Danish embassy in Beirut on fire in protest at the publication of cartoons depicting the Prophet Muhammad.
Thousands of people attended a rally and clashes broke out with security forces sent to protect the building.
Denmark urged its citizens to leave the country as soon as possible.
The violence came a day after mobs in neighbouring Syria torched the Danish and Norwegian embassies in Damascus in anger at the pictures.
Danish Foreign Minister Per Stig Moeller urged anti-Danish protesters in Muslim countries to calm tensions.
"It is a critical situation and it is very serious," Mr Moeller told Danish public radio.
The cartoons first appeared in a Danish newspaper in September and caused outrage among Muslims, who consider any images of Muhammad offensive.
One of the cartoons shows Muhammad wearing a bomb-shaped turban.
Newspapers across Europe have republished the pictures in recent days, saying they are defending freedom of expression.
Huge crowds attended Sunday's protest in Beirut. It turned violent after Islamic extremists tried to break though security barriers protecting the Danish embassy building.
Some 2,000 riot police and army troops fired tear gas and water cannons to disperse the crowd and fired their weapons into the air.
But smoke was later seen rising from the building after demonstrators broke into it.
Some protesters threw stones at the security forces and burned Danish flags.
Security officials said at least 18 people were injured, AP news agency reported.
The embassy building, which also houses commercial offices, was believed to be unoccupied.
Some people in the crowd are not happy with the violence, thinking this was going to be a peaceful demonstration, reports the BBC's Jim Muir from the scene of the violence.
He says some of the wilder elements in the crowd have succeeded in turning it into a very angry and quite violent demonstration.
In other developments:
- Hundreds of people rally in Afghanistan in protest at the cartoons
- Jordanian authorities arrest two tabloid editors for printing the cartoons
- Iran recalls its ambassador to Denmark
- An Iraqi militant group in the insurgent stronghold of Ramadi calls for attacks on Danish and non-Muslim targets in Iraq
- Britain's main opposition Conservative Party says slogans by anti-Danish protesters in London amount to incitement to murder
Denmark and Norway condemned Syria for failing to stop Saturday's attacks in Damascus and urged their citizens to leave the country.
"The principle of diplomatic relations is that diplomats can work safely and the fact that this has been broken is extremely serious," Norwegian Foreign Minister Jonas Gahr Stoere told a news conference in Oslo.
The US also criticised Syria's approach, saying it was "inexcusable" for such damage to be inflicted on diplomatic missions.
Published February 05, 2006, BBC