Polls opened in Venezuela on Sunday in an opposition-organized vote to measure public support for President Nicolas Maduro's plan to rewrite the constitution, against a backdrop of worsening political violence.

Dozens of people were queuing in Caracas neighborhoods including Chacaito and Los Palos Grandes before polling stations opened at 7:00 am (1100 GMT). Delegates and volunteers, many dressed in white, manned tents and tables.

The authorities have refused to greenlight a vote that has been presented as an act of civil disobedience and supporters of Maduro are boycotting it. So voters seemed set to reject the president's controversial plan.