ISLAMABAD, Pakistan — Pakistan said Monday it was investigating a group of foreigners -- including a Swedish man once held at the U.S. prison in Guantanamo Bay -- for ties to al Qaeda after they were detained on immigration offences.

Three other Swedes were also detained last month, including a woman and her 2-year-old son, after they entered the country from Iran and headed to North Waziristan -- a lawless, militant-riddled tribal area along the Afghan border -- allegedly to join al Qaeda operatives hiding there, according to a police report obtained last week by The Associated Press.

Also captured were seven Turks, a Russian, an Iranian, and a former Pakistani paramilitary soldier who deserted years ago.

"The indicators we have so far are they have been associated with al Qaeda," Interior Minister Rehman Malik told reporters in Islamabad on Monday. Commenting on the Swedes, Malik added, "They are Swedish nationals, but basically they are criminal and they were here on some other mission."

The group was seized Aug. 28 on the outskirts of Dera Ghazi Khan town in Punjab province. They all entered Pakistan illegally, Malik said.

"Two of them have previously been linked to al Qaeda," he said. "Obviously, we are treating them following all human rights rules, but they are under investigation."

The group was wearing burqas -- the all-encompassing garment worn by Muslim women -- when they were stopped by police.

One of the Swedes detained, Mehdi-Muhammed Ghezali, was previously held in Guantanamo Bay, Cuba, but was released in 2004. Ghezali, in his 30s, was part of a group of 156 suspected al Qaeda fighters captured in 2001 by Pakistani authorities while fleeing Afghanistan's Tora Bora mountains.

He has denied ties to al Qaeda and said he was in the region only to learn more about Islam.