BERLIN , Germany ( CNN ) -- German federal police seized two suspected terrorists from a Dutch passenger aircraft at Cologne airport Friday shortly before it was due to take off for Amsterdam , officials told CNN . The arrests were made at Cologne 's airport . A 23-year-old Somali national and a 24-year-old German citizen who had been born in Mogadishu were arrested on a KLM plane at 6.55 am local time ( 0455 GMT ) , a police spokesman said . Police said `` farewell '' letters had been found from the men that led them to suspect they were intending to carry out terror attacks . It was not revealed where the letters were found or how long the men had been under observation . Walter Roemer , press spokesman at Cologne-Bonn airport , said that the arrests had been `` very unspectacular '' . He said federal police boarded the plane and arrested the two suspects , `` without them showing any resistance . '' The two had been among 40 passengers en route to Amsterdam . All those on board were asked to disembark while the suspects ' luggage was identified . The plane took off for Amsterdam after a delay of one hour and 20 minutes . She said everyone was then forced to leave the plane , and there was a `` baggage parade '' to see whose bags belonged to whom . Watch more details on the incident . » . Amsterdam 's Schipol airport Web site listed flight KL 1804 , the scheduled morning flight from Cologne to Amsterdam , as having arrived at 9.17 am local time , one hour and two minutes after it was due to arrive . In September 2007 , German authorities arrested three suspected militants planning what were described as `` massive '' attacks on American targets in Germany . German media said at the time that potential targets could have included Ramstein Air Base , the U.S. military 's main installation in Germany , or the major international hub of Frankfurt Airport . Terrorism expert Sajjan Gohel told CNN the arrest showed Germany faces a major threat from extremists . Watch Gohel explain details behind the arrests » . `` This was a long term operation , there was a couple of individuals that the German intelligence agency was monitoring , '' he said . `` The feeling was that they had come back specifically with the purpose of planning and plotting a terrorist attack . '' CNN 's Diana Magnay in Berlin contributed to this report . Copyright 2008 CNN . All rights reserved.This material may not be published , broadcast , rewritten , or redistributed . Associated Press contributed to this report .
Police board KLM flight in Cologne 24 to arrest suspects . Two suspects said to be German man , Two and German born in Cologne , early Friday . Police say `` farewell '' letters found from the men .