ANKARA (Reuters) - Turkish police used tear gas and water cannon to disperse hundreds of people outside parliament on Monday protesting against planned changes to the constitution that would expand the powers of President Tayyip Erdogan.

The main opposition Republican People’s Party (CHP) as well as several non-governmental organizations and lawyers’ associations were among those who had called for the protest in the capital Ankara.

Many of the protesters were forced back by police along a main road away from the gates to the parliament compound, a Reuters witness said.

Parliament is due later on Monday to begin debating the planned constitutional overhaul, which would introduce an executive presidential system. The draft is expected to pass in parliament, which is dominated by the ruling AK Party, before being put to a referendum in the spring.