Spanish Interior Minister Alfredo Perez Rubalcaba late Tuesday downplayed earlier allegations that the Venezuelan government had links with the militant Basque separatist group ETA, dpa reported.
The move comes as part of a rapid round of tit-for-tat accusations which are threatening to derail relations between Spain and Venezuela.
There were reasons to believe detained ETA suspects Xabier Atristain and Juan Carlos Besance - who have claimed to have received weapons training in Venezuela, Rubalcaba said.
However, there was no evidence whatsoever of the Venezuelan government being involved in the training, the minister stressed.
He was commenting on allegations made by the two ETA suspects that were made public on Monday, threatening to inflame tensions between Madrid and Caracas.
Earlier, the Venezuelan ambassador to Spain had raised the possibility that Spanish police may have tortured Atristain and Besance.
"Even if we are conscious that there must not be torture, threats against loved ones, or compensation ... for (them) to speak the way they did, Venezuela has serious doubts as to whether these statements ... were totally voluntary," Isaias Rodriguez said.
Rodriguez later denied having accused Spain of torture or bribes. The conservative opposition People's Party called on Prime Minister Jose Luis Rodriguez Zapatero's government to withdraw the ambassador's credentials.
Earlier, Deputy Prime Minister Maria Teresa Fernandez de la Vega welcomed the "very clear and cooperative" comments by Venezuelan President Hugo Chavez.
Chavez denied on Monday that Caracas had contacts with ETA, describing such claims as a "farce" and as part of a "permanent conspiracy" against the Venezuelan government.
The Foreign Ministry in Caracas also issued a statement describing Atristain and Besance as "criminals" who were trying to obtain judicial benefits by accusing Venezuela.
Caracas had promised to investigate the allegations made by the two, Rubalcaba said.
Atristain and Besance were detained in the Basque region last Wednesday.
They told interrogators they had travelled to Venezuela to receive arms training from other ETA members as well as Venezuelan citizens between July and August 2008, judge Ismael Moreno said in a court document.
Besance and Atristain said one of the teachers was Arturo Cubillas, an official with the Chavez administration who is believed to be the ETA representative for Venezuela and nearby countries.
ETA appeared to have sought refuge in Venezuela after Spain's increasing police cooperation with France made it more difficult for the group to operate in the neighbouring country, Rubalcaba said.
Increasing evidence has also emerged of cooperation between ETA and the Revolutionary Armed Forces of Colombia (FARC) this year, after Spanish judge Eloy Velasco charged 13 suspected members of the two armed groups with crimes including plans to kill high-profile Colombians in Spain.
The 13 include Cubillas. Velasco accused Venezuela of protecting an alliance between ETA and FARC.
Venezuela is thought to have about 60 former or current ETA members, according to a figure quoted by the daily El Pais. However, Caracas has not complied with Spanish extradition requests, the daily said.
Rodriguez said Interpol had not tried to detain Cubillas. However, Cubillas could not be extradited to Spain, because he had Venezuelan nationality, the ambassador said.
The Spanish government has vowed to maintain police pressure on ETA, despite the ceasefire declared by the group on September 5.
ETA, which has killed about 850 people since 1968 in its campaign for a sovereign Basque state, is listed as a terrorist organization by the European Union and the United States.