GENEVA, Feb. 1 (Xinhuanet) -- The Swiss government on Wednesday granted permission for overflights by non-commercial U.S. aircraftafter receiving "clarification" from Washington concerning CIA planes carrying prisoners.

    The overflight license will be effective until the end of 2006,and it could be withdrawn at any time, government spokesman Oswald Sigg told reporters.

    Previously the Swiss government had only extended the overflight rights until the end of January as it was waiting for a response from Washington concerning CIA planes allegedly carrying suspected terrorists for secret interrogation in Eastern Europe.

    "The Swiss foreign ministry and the environment, transport, energy and communications ministry finally issued the permit because it had received the requested clarifications", Sigg said.

    He said the "clarifications" were provided by Washington on Monday, which stated officially that the CIA had used neither Swiss airports nor airspace to transport prisoners.

    Washington also said that it had always respected Swiss sovereignty in the past and would continue to do so in the future.

    The new permit is also intended to simplify proceedings, said Sigg, adding that in addition to the U.S., 25 other countries and two international organizations have been granted a general overflight license until the end of the year and they can now fly over Switzerland without having to apply for a separate permit each time.

    The Swiss authorities retain the right, however, to intervene and run checks in suspicious circumstances, Sigg said.

    At least 73 flights were made over Switzerland by U.S. planes suspected of being used by the CIA to transfer prisoners between 2001 and December 2005, according to the Swiss Federal Civil Aviation Office.

    The Federal Prosecutor's Office opened an investigation into the suspected CIA overflights in Swiss airspace and territory last November.

    The Swiss foreign ministry also had sought clarification about the flights from Washington.

    Swiss senator Dick Marty, who is heading an investigation into the affair for the Council of Europe, issued an interim report one week ago.

    He said he had no concrete proof of CIA detention centers in eastern Europe or elsewhere.

    However, he said European governments probably knew about CIA abductions and the transfer of detainees through European airspace.Enditem