Investigators have begun interrogating seven foreign al Qaeda suspects to determine possible links with locals, officials said on Monday.
The seven, including two women, were arrested on Sunday in a pre-dawn raid on an apartment in Karachi, where scores of al Qaeda suspects have taken refuge.
"They are being interrogated about their nationalities and true identities," the senior intelligence official told AFP.
"We are also trying to find out their possible links with local militants as the apartment where they were staying was arranged by a member of a religious party." He did not name the party.
Interior Minister Faisal Saleh Hayat said that the men were using the apartment in Karachi as a "hideout" from which to conduct terrorist activities, apparently outside of the country.
"They used the apartment as a hideout to carry out their operations, but our agencies were after them and did a fine job," Hayat told AFP.
"So far they have not been found involved in any terrorist activities in the country," the minister said.
Information Minister Sheikh Rashid said that one of the suspects was wanted for activities beyond Pakistan.
"We were looking for one of the foreigners involved in terrorist activity outside Pakistan," Rashid told AFP.
The intelligence official identified the suspect as Fazal Mohammad Abdullah al-Misri, who is considered an expert in making high-intensity bombs.
The detainees also included two Yemenis, an Afghan woman, and an Egyptian couple, he added.
Documents and weapons, including hand grenades and pistols, were recovered from the suspects, Rashid said, adding that more arrests were expected.
Hayat said extradition plans could only be considered once the suspects' nationalities and the nature of their activities were confirmed.