Hong Kong is sliding towards becoming a police state, US senator Josh Hawley warned on Monday, as tens of thousands filled the strife-torn city's streets waving American flags and calling on Washington to punish China over sliding freedoms. The international finance hub was battered by another weekend of unrest as hardcore pro-democracy protesters and police fought running battles with officers warning the violence had now reached "life-threatening levels". Protests pushing for greater democratic freedoms and police accountability have raged for the last 19 weeks and there is little end in sight as Beijing and local leaders refuse concessions.