CAIRO -- One of Osama bin Laden's sons has called on

Iran's

supreme leader to release members of his family believed to be under house arrest there since they fled

Afghanistan

in 2001, according to a letter posted Monday on the Internet.

Khalid bin Laden's statement accused Iranian authorities of mistreating about 30 siblings, saying they had been "beaten and repressed."

The letter, which was dated early January, appeared to have been written shortly after news reports surfaced about of one his sisters who escaped from her Iranian guards and reportedly is taking refuge in the Saudi Embassy in Tehran.

It has long been believed that Iran has in custody a number of bin Laden's children who fled Afghanistan in 2001 following the Sept. 11 terror attacks on the U.S., most notably his sons, Saad and Hamza, who were thought to have held positions in al-Qaida.

But Iran never confirmed it, and claimed to have been surprised to discover 17-year-old Eman was at the Saudi Embassy.

Little is known about Khalid bin Laden, who is said to be in his 20s and believed to have been with his father in Afghanistan until 2001. The letter identified him as Sheik Khalid, a reference to a holder of an esteemed religious position.

Iranian officials have said they knew bin Laden's daughter was at the Saudi Embassy but denied knowledge of how she got to Iran or when. Tehran also has never confirmed it was holding other members of the bin Laden family.

The letter posted Monday was addressed to Supreme Leader Ayatollah Ali Khamenei. Khalid bin Ladin insisted his relatives were in Tehran and expressed surprise at denial of Iranian officials of knowledge of their presence.

He said his family members, mostly women and children, were forced to flee to Iran "informally" from Afghanistan because of the U.S. air strikes in 2001 following the Sept. 11 attacks, and were detained by local authorities within a year.

"We learned of it and we communicated with the Tehran government many times," he wrote. "We asked scholars and dignitaries to mediate their release promising they won't return to Iran. But to no avail."

Another bin Laden son Omar told the Saudi-owned Asharq Al-Awsat newspaper in December that the family had not been certain about the fate of the siblings who fled through Iran until Eman provided the information after her escape. He said those detained included four siblings and 25 other relatives.

Eman said Saad had escaped from the house arrest about a year earlier - something confirmed in Khalid's letter.

Saudi officials have said they were mediating the girl's release but there has been no further word about her.

Khalid said he was surprised by the denial "despite the fact they were imprisoned and locked up in detention facilities for years. This is difficult to understand."

U.S. officials said last year Saad bin Laden may have been killed by a U.S. airstrike in Pakistan, after fleeing from Iran, but they could not confirm the information.

Khalid's letter confirmed Saad's escape, adding that Saad had informed him of the situation in Iran and said his siblings were "beaten and repressed."

"If the wise ones were informed of what he told us, the tragedies and hardships that our family suffered in prisons and detention facilities causing psychological diseases for the women and children, they would have undoubtedly hurried to release them," Khalid's letter said.

A 2009 book by Omar bin Laden and his mother, Growing Up bin Laden, said Khalid is son of Siham, one of the leader of al-Qaida's five wives. The book said if Khalid survived the 2001 bombings, he would most likely be living with his parents in Pakistan.

He is born in 1989 in Jeddah, Saudi Arabia.

http://www.washingtonpost.com/wp-dyn/content/article/2010/03/15/AR2010031501090_pf.html

© 2010 The Associated Press