Weeks of political unrest have claimed another victim as Venezuela's opposition prepares for another mass protest.

The Interior Ministry said Sunday that Almelina Carrillo died in a hospital after being struck on the head with a frozen water bottle thrown from a high rise during a pro-government rally last week. At least 21 people now have been killed since the unrest began almost a month ago over the Supreme Court's decision to gut the opposition-controlled congress of its powers.

News of the death comes as opponents of President Nicolas Maduro are set to flood highways across the nation Monday for a daylong sit-in.

Maduro on Sunday said he wouldn't give in to opponents and again urged them rejoin negotiations they broke off last December.