Islamabad and Washington announced that a Pakistani known to be the oldest detainee at Guantanamo Bay returned to his country today, Saturday, after 18 years of detention on the grounds of suspected links with Al-Qaeda, which Washington accused of being involved in the events of September 11, 2001.

Saifullah Paracha, 75, a Karachi-based businessman, was arrested for the first time in Thailand in July 2003 and transferred to the US military base in Bagram, Afghanistan, before being transferred in 2004 to the US naval base in Guantanamo Bay, Cuba.

"We are delighted that a Pakistani, who was detained abroad, is finally reunited with his family," the Pakistani Foreign Ministry said in a statement.

The US Department of Defense confirmed the repatriation of the Pakistani, and said in a statement that Paracha's continued detention was no longer necessary to protect US security from a "significant threat".

Paracha is the latest to be released from the detention camp - which was set up after the US-led invasion of Afghanistan in pursuit of Al-Qaeda, which it accuses of being behind the attacks that killed nearly 3,000 people in New York, the Pentagon and rural Pennsylvania on September 11, 2001.

Paracha, who had studied in the United States, was in the import-export business supplying major retailers in the United States.

The US authorities accused him of communicating with Al-Qaeda figures, including Osama bin Laden and Khalid Sheikh Mohammed.

Paracha, who, like many detainees, was not formally charged, was released after US President Joe Biden agreed last year to release him along with Pakistani Abdul Rabbani, 55, and Yemeni Othman Abdul Rahim Othman, 41.

Biden is under pressure to release unaccused prisoners at Guantanamo, and to move forward with the prosecution of those accused of being directly linked to al-Qaeda.