The business-focused social network was alerted to the issue after an investigation by the Tony Blair Institute for Global Change. The lectures were linked to 9/11 attack.
The Microsoft-owned business has since removed the material. But it faces criticism for not having taken a more proactive stance ahead of the discovery.
Before they were removed, they had collectively attracted more than 21,000 views.
They included:
a lecture arguing democracy is in contradiction to Islam
a call for Muslims to commit violence and seek martyrdom
a demand Muslims help finance jihadist activities
an order for retaliation against cartoons depicting the Prophet Muhammad
advice that children do not need their parents' permission to engage in jihadist activities
The authors included Anwar al-Awlaki, a radical American cleric who met two of the 11 September 2001 hijackers before their attack, as well as being linked to other plots before his death in 2011.
They also featured Omar Bakri Muhammad, a Syrian-born preacher who once lived in the UK and has claimed to have helped radicalise one of the killers of murdered soldier Lee Rigby.