CAIRO, Nov 29 (Reuters) - The assembly drafting Egypt's new constitution voted on Thursday to keep "principles of sharia" - Islamic law - as the main source of legislation, language unchanged from the previous constitution in force under former President Hosni Mubarak.

The issue was the subject of a long dispute between hardline Salafi Islamists and liberals in the assembly which will vote on each of 234 articles in the draft constitution before it is sent to President Mohamed Mursi for approval.

After that, Mursi must put it to a popular referendum. (Writing by Tamim Elyan; Editing by Robin Pomeroy)