Spain claims to have zero tolerance for doping.

The Spanish government has 'zero tolerance' for doping, Deputy Prime Minister Alfredo Perez Rubalcaba said Friday.

The comments came a day after steeplechase world champion Marta Dominguez and 13 others - including two of her coaches, her agent and doctor Eufemiano Fuentes - were detained on charges of involvement with a doping ring supplying athletes with banned substances.

On Friday, European 1,500m champion Nuria Fernandez and Ethiopian- born European cross country champion Alemayehu Bezabeh were called to testify as witnesses, along with fellow athletes Reyes Estevez, Eugenio Barrio and Digna Luz Murillo, El Pais reported.

None of them was arrested 'since there is no evidence of their involvement in the doping substance distribution network,' the report said.

Rubalcaba called the Dominguez arrest 'very bad news,' but emphasized that 'many people compete honestly for their country.'

'It would be terrible if, because a few, important as they may be, cheat, it would be thought that everyone cheats,' the vice premier said.

'Operation Greyhound' was launched in April, when investigators found evidence that a network of people might be facilitating illegal blood transfusions among sports professionals.

Police Thursday raided the homes of athletes, coaches and doctors in Madrid, Las Palmas, Alicante, Segovia and Palencia. They seized large quantities of steroids, hormones and medication including erythropoietin (EPO), along with bags containing blood and documents about doping practices.

Several Spanish athletes on Friday expressed support for the operation, which they said gives them 'new hope for a cleaner future.'

'We support ... the court process that has been launched. We think it is the right track towards the total eradication of doping from Spanish sport,' said a statement signed by scores of athletes including Manuel Martinez, Juan Carlos Higuero, Ruth Beitia and Mayte Martinez.

'So far, systems for the detection of banned substances have not given the desired results,' they said. 'Cheats have enjoyed an impunity that despaired other sportspeople, who saw themselves condemned to competing at a disadvantage.'

El Pais reported that Alemayehu admitted to having taken banned substances. He was excluded Thursday from the Spain delegation that was to take part Sunday in the European cross country championships in Portugal, where he was regarded as a favourite.

Nuria Fernandez, however, is set to take part in the championships, although Manuel Pascua, the coach she shares with Alemayehu, was arrested Thursday.

The IAAF could only intervene after the police investigation concluded and if it could access the evidence, sources from the ruling athletics body said.

Dominguez, 35, won the 3,000m steeplechase world title 2009 in Berlin and is a European 5,000m champion from 2002 and 2006.

She will miss the 2011 season as she is pregnant, but reportedly plans to return in 2012 for the London Olympics.

She was questioned for eight hours and later released. Three other suspects - a cycling trainer and two pharmacists - were also released.

Suspects detained in Madrid, including Fuentes, were to be questioned by judges from Sunday onwards. Dominguez was expected to appear in court in her home city of Palencia, but the date for the hearing has not yet been set.

This investigation is the third of its kind directed against doping in Spain.

Last year, 20km race walker Francisco Fernandez, a 2006 European champion and 2004 Olympic silver medallist, was banned after Operation Grail.

In 2006, the physician Fuentes was at the centre of the biggest probe so far, Operation Puerto, which targeted cyclists, team officials and doctors over blood doping.

Fuentes was not punished at the time because Spain only introduced anti-doping legislation later in 2006.