Tripoli: Muammar Gaddafi tried to engineer a `political` marriage between his second son and planned heir and one of Russian president Vladimir Putin`s daughters, a former advisor to the late Libyan dictator has claimed.

Gaddafi approached a bemused Putin to ask if one of his daughters could wed his second son Saif al-Islam Gaddafi, with the aim of strengthening ties between Libya and Russia, Mohammed Abd El Motaleb al-Houni told al-Arabiya.

"Gaddafi talked about it with Putin, proposing his son as a future son-in-law, but the Russian President was taken aback and said his daughter did not know Saif al-Islam," al-Houni said.

Gaddafi was ousted and killed in a NATO-back revolt in 2011. Saif al-Islam was in July sentenced to death by a court in Tripoli in a mass trial of former regime figures widely criticised by human rights groups.

Saif al-Islam has been in custody in the Libyan mountain town of Zintan since he was caught trying to flee Libya in the aftermath of the 2011 revolution. The militia holding him has refused to hand him over.