Joseba Beloki, a 39-year-old former racer with ONCE and Liberty Seguros declined, saying he would have to think about it.

Isidro Nozal, a 35-year-old former rider with the ONCE, Astana and Karpin-Galicia teams, also refused to give the court permission to analyze his DNA.

"No, I don't want to," he said and added "I don't see why I should have to."

The riders were among four former Spanish professionals giving evidence under cross-examination on Tuesday.

Only Nozal acknowledged ever having received treatment from Eufemiano Fuentes, the doctor at the center of the Puerto case.

Fuentes is the key figure and one of five defendants in the case, which stems from a police raid in 2006 that uncovered blood bags and other doping equipment and implicated many of the world's top professional cyclists.

No riders are on trial because doping was not illegal in Spain at the time and the court is limited legally to trying Fuentes and his co-defendants, which include his sister Yolanda, of endangering public health.

Beloki said he was willingly collaborating with the case, although he had been subpoenaed to appear as a witness. He has denied any links with Fuentes.

"But if you ask me if I give my permission to have the blood bags analyzed, I would have to think about it," he told the court via a video link.

The former racer was withdrawn from the Tour de France in 2006 after his name became implicated in the Puerto case, although he was cleared by Spanish officials of any wrongdoing in July that year.

Beloki also denied that a document presented by state prosecutor Rosa Calero, which had been seized by police in one of the properties allegedly used by Fuentes for blood doping, was his former training schedule for 2005.

He acknowledged that a number written down on the document was "my house phone," but said the calendar did not coincide with his activities as it did not contain the Spanish Vuelta, which he participated in.

Nozal, who at times under cross-examination appeared confused and ill at ease, acknowledged he had been treated by Fuentes. But he said the only times blood was extracted from him was for "health analysis reasons."

"I have never taken performance-enhancing drugs," he said adding "I failed a drug test in 2009 for EPO, but you should ask the doctor then about that."

David Etxebarria, 39, who rode for ONCE and Liberty Seguros, among others, denied he had ever had any contact with Fuentes.

"Fuentes never did an analysis for me," he said. "I am 100 percent sure none of the bags seized at Fuentes' place are mine."

Etxebarria said he would be happy to give a DNA sample for authorities to compare with the bags.

37-year-old Unai Osa who rode for the Illes Balears-Banesto and Liberty Seguros teams, said he could only remember being treated by official team doctors and not Fuentes.