The man whose arrest in February sparked Libya's revolution was sworn in as a minister in the new interim government on Sunday but said he had been hesitant about taking on the new job.

Fethi Tarbel, Libya's new sport and youth minister, wiped away tears after he took he swore a pledge of allegiance to Libya with one hand placed on the Koran, the Muslim holy book.

Standing in front of Prime Minister Abdurrahim El-Keib and National Transitional Council (NTC) chairman Mustafa Abdel Jalil, Tarbel was among a small group of ministers who had not taken part in the first inauguration of Libya's government last month.

The interim government will lead the North African country still reeling from a civil war that toppled dictator Muammar Gaddafi to elections in seven months' time.

Tarbel, a human rights activist and lawyer who represented families of the Abu Salim prison massacre in 1996, was arrested in Benghazi in February.

His detention sparked a demonstration by families of the victims of the Abu Salim massacre in the eastern town's Shajara Square on the night of Feb 15-16. They were then dispersed by police, which sparked larger riots on Feb 17 that began Libya's uprising.

Tarbel, 39, told Reuters that he was reluctant at first to take up his post when El-Keib asked him, as he already sat on the NTC in Benghazi.

I told him 'No I can't because there was an agreement that NTC members should not accept posts as ministers', he said.

But he then announced my name as minister for youth and sport when he announced his government. I asked him to give me three days to think about it.

Tarbel said he asked advisers, family and NTC members about taking up the post but they advised him against it.

Most of them said that it was better if I didn't accept it as it is a big ministry with a huge task. Most of the Libyan population is young, he said.

After that I accepted, and I don't know how I did it.

Other ministers sworn in on Sunday included Defence Minister Osama Al-Juwali and Oil Minister Abdulrahman Ben Yazza.

(Reporting by Ali Shuaib; Editing by Michael Roddy)