Madrid, 19 August (AKI) - Police wielding batons dispersed around 150 people in Spain's capital, Madrid on Friday protesting a visit by Pope Benedict XVI to mark the 2011 World Youth Day celebrations. The four-day visit began on Thursday and has been overshadowed by violent protests.

Some protesters were quoted as saying police had manhandled them and hit some with truncheons, although a spokeperson for Madrid emergency serviced they had had not attended to any injured.

Police earlier cordoned off the central Puerta del Sol square and used vans to hem in demonstrators furious at the cost of the papal visit at a time of austerity in Spain. The square was the birthplace of Spain's widespread "indignant" protests earlier this year over the handling of the ailing Spanish economy and was the scene of clashes late Thursday between demonstrators and police.

The demonstrations against the visit - Benedict's third one to Spain - have turned unusually aggressive, with protesters and pilgrims shouting at each other in Madrid city centre and police charges against demonstrators in which more than a dozen people were injured on Thursday and Friday and seven were arrested on Wednesday.

Eleven people were injured in the clashes late on Wednesday including two officers, and a Mexican chemistry student was detained for allegedly planning to attack an anti-Pope march with "asphyxiating gases and other substances", police said.

More than 100 groups opposed the pontiff's visit, including the 15-M movement - which opposes the government's austerity measures - as well as gay right groups and other opposed to aspects of Catholic teaching.

The protesters including some priests, are especially critical of the cost of the papal visit - estimated at 50 million euros - when Spain is facing economic hardship. The unemployment rate is over 20 percent with youth joblessness at 45 percent and the government is cutting public spending to stave off a sovereign debt crisis.

Organisers say they believe the event - which has drawn about one million pilgrims fro nearly 200 countries - will generate about 100 million euros for the Spanish economy and claim that pilgrim registration fees have footed much of the bill.

But critics say the event will cost a similar sum, although the government has reportedly declined to give any cost figures.

Benedict on Friday urged young people to exercise "Gospel radicalism"in a world of "relativism and mediocrity". He was speaking at a meeting with around 2,000 young nuns at the El Escorial near Madrid. He earlier visited King Juan Carlos and other members of the royal family at the Zarzuela palace.

He was slated later Friday to meet prime minister Jose Luis Rodriguez Zapatero, who is seen as favouring greater separation between church and state. Zapatero's Socialist government has enacted reforms such as gay marriage, stem-cell research and easier access to abortion, making Spain one of Europe's most socially liberal countries.

The 84-year-old pontiff received an ecstatic welcome on his arrival in Madrid Thursday from hundreds of thousands of pilgrims at a gathering in Cibeles square, where he indirectly criticised abortion in a reference to those who "creating their own gods take it upon themselves to decide who should live and who can be sacrificed in the interests of other preferences."

Large crowds continued to turn out on Friday, cheering and waving flags as the popemobile drove by. During his visit, Benedict has voiced concern over unemployment and Europe's share of responsibility for the economic crisis while harshly criticising "superficial and consumeristic" modern culture.

The World Youth Day 2011 festivities began on Tuesday with a giant-open-air Mass where around 800 bishops, archbishops and cardinals from around the world and 8,000 priests tended to the congregation. They end on Sunday.