Madrid - Spain's former government authorized US flights transporting terrorist suspects to make stopovers in Spain, and tried to keep the illegal flights secret, the daily El Pais reported Monday.

El Pais on Sunday published a top secret Foreign Ministry document dating from 2002 and showing that the United States had requested permission for CIA flights to make "emergency landings" in Spain.

The document clearly states that the flights transported Taliban and al-Qaeda prisoners from Afghanistan to the US military base in Guantanamo, Cuba.

Then prime minister Jose Maria Aznar's conservative government granted the permission within 24 hours, according to the daily.

Aware that the flights were illegal, the Aznar government recommended that they use the "discreet" airports of Moron de la Frontera and Rota, two US military bases in Spain, the daily said.

Both the former and the current Socialist governments have denied knowledge of anything illegal having occurred on US flights via Spain.

On Sunday, Foreign Minister Miguel Angel Moratinos said Aznar's People's Party (PP) had not informed the Socialist government about an authorization given to the US to transport prisoners.

Moratinos announced an internal investigation into the affair.

Spain's National Court is currently investigating alleged CIA flights via Spain.

The government has handed the court documents on 11 flights to or from Guantanamo making stopovers in Spain - and 13 others which used the Spanish airspace - between 2002 and 2005.

Spain was one among several countries from which Washington requested permission for prisoner transport in 2002, according to El Pais. The other countries included Turkey, Italy and Portugal.

Former foreign minister Josep Pique, who allegedly was aware of the permission granted to the US, declined to comment immediately on the El Pais report.

A Council of Europe 2006 report named Spain as one among several countries having allowed secret US flights carrying terrorist suspects. (dpa)