US authorities helped Danish security officials locate the terror suspects in an alleged bombing plot unearthed this month through an electronic intercept from Pakistan, where one of the men had received training at an al-Qaeda camp.

The method was similar to that adopted during arrests of some suspects in a bombing plot in Germany [Images], a media report claimed on Monday, quoting intelligence officials in Washington. One of the men in the Danish case received instructions about explosives, surveillance and other techniques at a terrorist training camp in Pakistan near the border with Afghanistan, The New York Times quoted the officials as saying.

Intelligence officials in Denmark and Washington were quoted as saying that at least one suspect in the Danish group had direct ties to leading figures in al-Qaeda, which has regrouped in north-western Pakistan.

"They are now able to give military and terrorist training and able to plan and steer specific operations in Europe," Jakob Scharf, the Danish intelligence chief, told The New York Times. He added, "The al-Qaeda is back."

Scharf drew a clear distinction between independent or loosely affiliated groups drawing inspiration from al-Qaeda's ideology and specific control of plans of attack, saying the Danish bomb plot was clearly the latter.

This is the first time that officials have linked the terror operation in Denmark to the group that masterminded the terrorist attacks of September 11, 2001 on the United States.

The release of six of the eight men arrested in connection with the Denmark terror plot had fuelled skepticism about the strength of the case and the government's ability to turn arrests into convictions.

Denmark is a likely target for Islamic fundamentalists as it published the blasphemous cartoons of the Prophet, which incited violent protests across the world.