PML-N senior leader and former foreign minister Khawaja Asif has been arrested by the National Accountability Bureau (NAB) in Islamabad, a spokesperson for the bureau confirmed on Tuesday.

"NAB Lahore has arrested Khawaja Muhammad Asif in assets beyond known sources of income case," the official told DawnNewsTV.

According to the bureau's spokesperson, the PML-N leader had earlier been summoned for an inquiry but he failed to provide the required evidence.

The spokesperson said Asif held an iqama (work permit) from 2004 to 2008, adding that he claimed to have earned a total of Rs136 million for his services as a consultant legal adviser.

The PML-N leader was directed to submit details of the salary he received and other information. He was also asked to provide the job application he had submitted to a foreign company as well as his iqama agreement.

"Khawaja Asif continuously failed to cooperate during the inquiry," the spokesperson said, adding that he was arrested with the approval of the NAB chairman.

The official said Asif would be presented before an accountability court on Wednesday to obtain his remand.

In a press statement issued later, NAB Lahore said that the investigation against Asif was being conducted under Section 5 of the National Accountability Ordinance 1999 and Section 3 of the Anti-Money Laundering Act 2010.

According to the statement, Asif was elected as senator in 1991, prior to which he had total assets of Rs5.1 million. By 2018, this figure had ballooned to Rs221 million, which is not justifiable with his known sources of income, said NAB Lahore.

Besides, the statement added, Asif was running a benami company in the name of his employee, Tariq Mir. A sum of Rs400 million was deposited in the bank account of the company, titled 'Tariq Mir and Company', but there was no information about the sources of income, said NAB Lahore.

Reacting to the development, PML-N supremo Nawaz Sharif in a tweet condemned the arrest, terming it a part of "the nexus of the selectors and the selected".

"Such ham-fisted acts reflect the government's state of panic, but they are moving even closer to their end through such actions," he wrote.

His daughter and PML-N Vice President Maryam Nawaz denounced the arrest, saying he had been "kidnapped by NAB".

She said Asif was leaving for a TV interview after attending a party meeting when he was arrested by NAB.

Maryam claimed that "someone" had called Asif and asked him to stop supporting Nawaz Sharif's narrative. When he refused, Asif was told to "be prepared for the consequences".

Maryam said the opposition's Pakistan Democratic Movement will react to the arrest, and "the reaction will be such that you will have to release Khawaja Asif."

She said the nation was looking towards the judiciary and that it "should not stay silent" on the matter.

PPP chairperson Bilawal Bhutto-Zardari, during a presser late on Tuesday, also condemned the arrest. “It is against the stability of Pakistan,” he said.

Earlier this year, NAB and the Anti-Corruption Establishment (ACE) had initiated action against the close confidant of former premier Nawaz Sharif on the allegation of illegally establishing a housing project in his hometown Sialkot.

According to NAB, evidence shows Asif established the Kent Housing Society, which has been operating illegally.

In November, NAB had sought records from him regarding sources and local amount of funds invested in the project by him, his family members (wife and son) and other partners/close relatives.

NAB says the former foreign minister had in collusion with the management of the society illegally occupied various pieces of land owned by individuals who never sold their land to the society.