"I want to send a message to the leaders of Pakistan: they should help the children of Osama bin Laden to go wherever they want to go. The Pakistani government should protect them, because they are just innocent children and women," Omar bin Laden told Reuters.
Omar, who is said to bear little resemblance to his father, said he has been based in the Qatari capital for a year to start his own property development company, Qatar bin Laden Group.
The bin Laden family amassed fortunes in construction and real estate, wealth that enabled Osama to fund and plan attacks against the United States and its ally Saudi Arabia, which he accused of going against the principles of Islam.
After the attacks in New York and Washington on September 11, 2001, Osama bin Laden was the subject of a massive manhunt that forced him into hiding.
At his last hiding place, a compound north of Islamabad, one of bin Laden's widows Amal Ahmed Abdulfattah, along with two other wives and several children, were among 15 or 16 people detained by Pakistani authorities. He is believed to have about 20 children from several wives.
Pakistan has blamed intelligence lapses for a failure to detect bin Laden, while Washington has worked to establish whether its ally had sheltered the al Qaeda leader, a charge Islamabad vehemently denies.
Omar said all of his relatives except for his sister Fatima and her husband have left Iran, where several of Osama bin Laden's children with his first wife Najwa fled in 2001.
"Thank god all except one have gotten out," Omar said.
He added that he was not convinced his father was killed in the U.S. military operation in Abbottabad, Pakistan, in May. He was also unsure whether his father had lived for five uninterrupted years at the compound where the raid took place.
"Why hasn't the U.S. shown the photos? If we haven't seen the body, we can't be completely sure," he said.
U.S. authorities say they decided not to release pictures because of the potential to incite violence and be used as an al Qaeda propaganda tool.
Omar said, however, that he was sure his brother Khalid was killed in the raid: "I saw the picture, and knew it was him."
Osama bin Laden's fourth-eldest son, Omar broke with his father in 2001 after living in Afghanistan for much of 1996 to 2001.
In "Growing up bin Laden," a book written by U.S. author Jean Sasson with Omar bin Laden and his mother, Omar said he wanted to tell his story to show the damage done by war.
(Editing by Sonya Hepinstall)