Photo Gallery Police Crackdown in Stuttgart

Around 600 police used water cannon, tear gas, pepper spray and batons in an operation against over 1,000 demonstrators in the southwestern city of Stuttgart on Thursday. The activists had tried to use a sit-down protest to prevent the city's Schlossgarten park from being cleared so that work could begin on felling trees in the park. The trees are being cut down as part of construction work for a new railway station project called Stuttgart 21.

Images of people bleeding from the eye after being hit by water cannon featured on German television and newspapers Friday. The protest's organizers said in a statement that more than 400 protestors had suffered eye irritation as a result of the police's operation, with some suffering from lacerations or broken noses.

Protestors try to protect themselves against the powerful high-pressure streams of water: The police operation has been criticized by opposition politicians.

Here, police are lined up in front of the main station on Friday, a day after Thursday's crackdown on protesters.

A demonstrator has his eyes rinsed with water after an encounter with pepper spray: The Stuttgart 21 project involves moving the city's main railway station underground and turning it from a terminus into a through station.

Thursday's protest drew a broad cross-section of residents from Stuttgart, including women, children and school students. Here, a boy defends a tree from getting cut down with a toy water pistol.

But police weren't up to child's play in Stuttgart. Those who refused to leave the area voluntarily were removed by force. The project is controversial partly because of its price tag -- it is slated to cost 4.1 billion ($5.38 billion) -- and because of the trees that will be cut down in the Schlossgarten park.

A protester throws a chair at police officers during the altercation on Thursday.

Here, demonstrators try to protect themselves against water canons.

"Stuttgart 21" opponents at the sit-in on Thursday: The protests were attended by a broad cross-section of society, including pensioners and children.

A spokesperson for the activists said the police had acted irresponsibly when dealing with the younger protestors -- some of whom were school children attending a legal demonstration.

Peter Hauk, floor leader for the conservative CDU in the Baden-Württemberg state assembly, turned the accusation on its head. "I think it's irresponsible of mothers and fathers that they not only take their children with them, but also put them in the front row," he said.

In the early hours of Friday, workers began cutting down the first of 300 trees that must be cleared to make way for for the rail project.

The felling of the first trees on Friday morning was accompanied by loud but peaceful protests from the large crowds of demonstrators.

A candle protest in the early hours of Friday: Another mass demonstration is planned for Friday evening.

In the end, the city continued to cut trees down so that the construction project can begin.