German police arrested two male terrorist suspects on a KLM aeroplane at Cologne airport this morning.
The men are suspected of wanting to take part in Islamist attacks after farewell letters had been found, a police spokesman told German television.
German news sources are reporting that a specialist police commando team stormed the plane at 6.55am and arrested the men.
A 23-year-old Somali and a 24-year-old Mogadishu-born German citizen were arrested on suspicion of planning to carry out a "jihad" attack, state police spokesman Frank Scheulen said on N24 television.
It is reported that police discovered 'farewell letters' during a raid on an apartment.
The two men are now being interrogated by the authorities, who also took their luggage from the plane, airport spokesman Alexander Weise said in a telephone interview.
The aircraft left for Amsterdam after an 80-minute delay, Weise said. The flight landed at Amsterdam's Schiphol airport at 9:17 a.m., 62 minutes behind schedule, according to the airport Web site.
Earlier this month, the head of the BKA Federal Criminal Office, Joerg Ziercke, warned that Germany was at high risk of attack by al-Qaeda terrorists.
In a report to parliament, Mr Ziercke said that a decision to target Germany has been made "at the highest level" of al-Qaeda and other terrorist groups, Bildnewspaper reported on September 11th.
The Federal Prosecutor said yesterday that authorities are searching for two suspected terrorists, 21-year-old Eric Breininger and 23-year-old Houssain Al Malla.
The BKA said today that the two wanted men were not connected with the Cologne airport incident.
Mr Breininger, a German from the western state of Saarland, is suspected of having trained at a camp in Pakistan with a terrorist group, Islamist Jihad Union, broadcaster ZDF said yesterday, citing unidentified security officials.
The officials told ZDF that the suspect, accompanied by Al Malla, has possibly returned to Germany where he may aide in carrying out an attack.
"If the security authorities publish a wanted letter like this, then the danger is certainly great," Guido Steinberg, of the German Institute for International and Security Affairs in Berlin, said in an N24 interview.
A year ago, German police seized hydrogen peroxide-based explosives more powerful than the bombs used in the Madrid train attacks of March 2004 or London subway and bus bombings in July 2005. The bombers were targeting US citizens and facilities in cities including Frankfurt, Dusseldorf, Munich, Cologne and Stuttgart, prosecutors have said.
Additional reporting: Bloomberg