"As possible targets ... the suspects named discotheques and pubs and airports frequented by Americans with a view to detonating explosives loaded in cars and killing or injuring many people," Federal Prosecutor Monika Harms told a news conference in Berlin on September 5.

The suspects, two Germans aged 22 and 29 and a 29-year-old Turk, received terrorist training in Pakistan and had close ties to al Qaeda, according to Jorg Ziercke, president of Germany's Federal Criminal Investigation Office.

Ms Harms said the three suspects are members of the German cell of a group named as Islamic Jihad Union. She said the group had amassed 680 kg of hydrogen peroxide to make bombs that would have been among the biggest yet on German soil. Possible scenarios would have been car bombings used in simultaneous attacks.

Officials said the hydrogen peroxide -- the same chemical used in the London transport bombs that killed 52 people and four terrorists in 2005 -- could have produced a bomb with the explosive power of 540 kg of TNT.

Frankfurt airport is a popular international travel hub while Ramstein air base is a major transit point for the US military into the Middle East and Central Asia.

The German terror arrests came a day after Danish police arrested eight "militant Islamists," accusing them of storing "unstable explosives."