In the wake of the arrest of a U.S. citizen of Pakistani origin in New York, Pakistani law-enforcement agencies swung into action on Tuesday and nabbed several suspects, local newspapers reported Wednesday.

The arrests came when the special investigation group of the Federal Investigation Agency (FIA) was tasked to investigate the car bombing plot in which Faisal Shahzad, a naturalized U.S. citizen arrested Monday late night, was allegedly found guilty.

The friend Tausef and father-in-law Iftikhar Mian of Shahzad were picked up by intelligence personnel from a house in southern city Karachi, the DAWN said.

According to the report, Faisal's immediate family, his wife Huma Mian and two children are also in Pakistan, but it could not be confirmed if his wife has also been detained.

Sources said that Faisal Shahzad had come to Karachi in 2009. He is son of Air Vice Marshal (retd) Baharul Haq, who retired in early 1990s. Later, he got a senior post in the Civil Aviation Authority (CAA) and his family moved to Karachi, the sources said.

Air Vice Marshal (retd) Baharul Haq has two sons. The elder son is settled in Canada.

Faisal had been living in the United States. His father lives in Hayatabad area of Peshawar in northwest Pakistan.

The Nation newspaper said Shahzad received militant training in Kohat, quoting an intelligence official. The area around Kohat is a stronghold of Tariq Afridi, the main Pakistani Taliban commander in the region, it said.

Meanwhile, the News reported that officials said several people had been taken into custody in Karachi since the failed attack Saturday. They said no charges had been filed.

According to the report, security officials in Karachi said they had arrested a Pakistani man who had spent time with Shahzad during a recent visit there. Investigators said they arrested the man, Muhammad Rehan, in Batkha Mosque in the North Nazimabad area just after morning prayers. The mosque is known for its links with the militant group, Jaish-e-Muhammad.

Investigators said Rehan told them he had rented a pickup truck and driven with Shahzad to Peshawar where they stayed from July 7 to July 22, 2009. The account could not be independently verified.

Karachi police officials, however, expressed disassociation with the developments and said they had not received any orders in connection with Faisal Shahzad.

"We didn't get any order, but at our end we have collected information which confirms that a young man by the name of Faisal Shahzad did arrive in Karachi in April 2009 and left in August the same year. We have received information that some of his relatives live somewhere in North Nazimabad and police are trying to locate the house," Capital City Police Chief Waseem Ahmed was quoted as saying.

In the eastern province of Punjab, police and intelligence personnel picked up a few suspects from different parts in connection with the recovery of explosives from a vehicle in New York, reports said.

Informed sources in the Punjab police said that the arrests had been made in Lahore and Rawalpindi.