Muslims in Spain are worried.
By Dominic Bailey
BBC News Online, Madrid
The Islamic centre in Madrid preaches tolerance
Exactly who was behind the Madrid train bombings is still not certain but three of the five being questioned are Moroccan, one of whom is reported to be linked to attacks in Casablanca last year.
There is a large Moroccan immigrant community in Spain and many fear reprisals against their families, businesses and places of worship.
Islamic leaders in Spain were quick to denounce the 11 March Madrid attacks, even though the finger of blame was initially pointed at Basque separatists Eta.
At least eight Muslims were among the 200 people killed and more than 40 among the hundreds of injured.
But talk of al-Qaeda links has again muddied the perception of Islam and made ordinary Muslims feel insecure in the land they have happily made their home.
Rumours of repercussions
The white stone and marble Cultural Islamic Centre and mosque stands out against the backdrop of high-rise flats along the M-30 motorway out of Madrid.
Inside it is a cool oasis of serenity that echoes with the imam's call to prayer.
But the number of prayer times has been reduced and entrance to regular visitors is restricted.
The centre's secretary, Mohamad Saleh, says the safety precautions are necessary.
"We are worried about the repercussions that there may be against Muslims," he said.
After 11 September eggs were thrown at the mosque and some Muslims were sacked from their jobs simply because of their religion.
There are already reports of abuse on the street, Arab businesses having windows broken and rumours of demonstrations outside the mosque being planned.
"We felt for the victims, the same as everyone, this sort of desperate terrorism affects all areas," said Mr Saleh.
"But people shouldn't punish a religion or country because of who commits a crime. If a Christian kills, are all Christians blamed? Are the Basques blamed if Eta attack?
MOROCCANS IN SPAIN
Moroccans are the largest immigrant group in Spain
In 2003 there were 333,000, 20% of all legal immigrants
The number of illegal immigrants is unknown
Thousands cross the eight-mile Straits of Gibraltar every year on rafts or small boats
In 2003 24,146 people were repatriated to Morocco
Many work as cleaners, farm labourers or building workers
Polls show that Moroccans are Spain's least-liked immigrants
"These people are terrorists and terrorists are criminals wherever they are from.
"They cannot have real faith or know God. For a Muslim to kill a person unjustly is to kill everyone. There is no justification to kill."
A banner reading "No to terrorism. Solidarity and condolences to the victims and their families" hangs under the arch of the centre's entrance.
There are about 500,000 Muslims in Madrid and on Fridays between 1,500 and 2,000 faithful pray at the mosque.
Most are from Morocco, Algeria and other Arab states.
Spain has a long, if bloody, history with its Arab neighbours to the south.
Many Arabic dishes, words and architecture survive in modern Spain, remnants from the Moorish conquest of the peninsula which ended in 1492.
But now, many immigrants who have made the country their second home don't feel safe.
A 46-year-old Algerian, who would not give his name, said there had been threats and people were afraid.
"I feel one of the people here and feel for them but I don't like the way they now look at us in the street," he said.
"A friend of my wife's came home pale and frightened the other day after a group of kids threatened her, shouting 'Dirty disgusting Moors'."
But he said the Spanish were genuinely good people and hopefully would move on with their lives.
Moroccan immigrant Rabii, 26, playing draughts with bits of cardboard outside the mosque, said it still had to be proved that al-Qaeda was to blame.
"The people coming over here are not here for jihad, they are coming here to find a better future. But now we can't go to the mosque and they are stopping us praying."
A greater concern for him was that the difficult task of finding a job would be made harder after the attacks.
After the pain, peace
Businessman Ahmed Jbari, 53, from Tangiers, says the adverse reactions are down to ignorance.
"Here in Madrid there is a mix of everyone, Jews, Muslims, Christians - it is like a big family and we all have our way of life.
"But people who break the windows should be blamed, not others. Here 29 pay for what one has done."
Moroccan street-seller Abdellate Fechaaui, 30, was among the hundreds of Muslims who joined the march of millions against terrorism after the Madrid attacks.
Abdellate and his colleagues had one message for the Spanish people and the bombers: "We are with the Spanish people and are feeling the same pain as everyone. We want peace."