COPENHAGEN, Denmark - Danish intelligence agents arrested eight alleged militants with links to leading al Qaeda figures early Tuesday and said the suspects were plotting an attack involving explosives.

"An act of terror has been prevented with the night-time arrests,'' said Justice Minister Lene Espersen.

Jakob Scharf, head of the PET intelligence service, did not identify the target of the plot but said the suspects -- six Danish citizens and two foreigners with residence permits -- had been under surveillance for some time.

He identified them as "militant Islamists with connections to leading al Qaeda persons.''

Terrorists have not hit Denmark in more than two decades, but the July 2005 bombings in London stirred fears that the Scandinavian country could be targeted for its participation in the U.S.-led coalition in Iraq.

Those fears grew after a Danish newspaper published 12 cartoons of the Prophet Muhammad, triggering fiery protests in Muslim countries in early 2006. Many Muslims considered the drawings blasphemous.

Scharf said the planned attack did not appear linked to the cartoons or Denmark's involvement in Iraq.

The suspects arrested Tuesday, ages 19 to 29, were not identified. All eight were arrested without incident in raids on 11 locations in and around Copenhagen, authorities said.

The suspects are of Afghan, Pakistani, Somali and Turkish origin, Scharf told reporters. He said Danish investigators had worked with "several foreign co-operation partners'' before making the arrests.

The TV2 News channel reported that a 19-year-old electrician was arrested in suburban Ishoej, while a taxi driver in his early 20s was arrested in Copenhagen's Noerrebro district. TV footage shot from a helicopter showed bomb squads and forensics agents at those locations.

In Ishoej, anti-terror police broke down the door of a Turkish family's apartment, Karina Elbaek, who lives on the floor below, told The Associated Press.

"They were ordinary neighbours, really friendly, helpful and extroverted,'' Elbaek said of the family.

Sadie al-Fatlawi, who lives on the floor above the cab driver in Noerrebro, said police ordered him and other neighbours to leave the building during the raid.

"When we came down to the police van they said that they suspected that there were some explosives in the property, or something that could burn very violently,'' al-Fatlawi told the AP.

The taxi driver was of Pakistani origin and had recently moved in, al-Fatlawi said.

Danish public radio DR identified a third suspect as a man of Afghan origin who had grown a beard and wore traditional Afghan clothing. He lived with parents and his two sisters in Avedoere, another suburb south of the capital, DR said, citing neighbours.

It is the third time Danish police have cracked down on suspected terrorist networks since 2005.

A separate trial of four men suspected of planning to blow up a target in Denmark or elsewhere in Europe is to begin in Copenhagen on Wednesday.

In February, a court sentenced Abdul Basit Abu Lifa, a Danish citizen of Palestinian descent, to seven years in prison for his involvement in a Bosnia-linked plot to blow up a target in Europe. Three other defendants were acquitted, although one is awaiting a retrial.