Hundreds of police officers in riot gear are on the streets of Admiralty, where tear gas and a water cannon have been used repeatedly against protesters throwing bricks and petrol bombs.

While tear gas has become a common sight in Hong Kong this summer, we haven't seen so many police officers on the streets in some time.

AP Photo/Kin Cheung

Today's scenes are reminiscent of June 12, right at the beginning of the unrest, when a large operation began to clear protesters from these same roads outside Hong Kong's Legislative Council and government headquarters.

That clearance came after protesters held the road for hours and were pushing toward other main streets. Today's deployment came much quicker, a likely sign of the shortening patience of local police. Tear gas and water cannon were also used much more quickly, following petrol bombs thrown by protesters at barricades and government buildings.

The government's tactics for dealing with the protests -- now in their 13th consecutive weekend -- appear to have shifted this week: Multiple pro-democracy activists were arrested on Friday, and a peaceful march scheduled for Saturday was banned.

AP Photo/Kin Cheung

After that march was called off, police appeared to prepare for major unrest, setting up barricades outside Chinese government offices and deploying water cannon vehicles.

While in past weeks, police have been satisfied to keep protesters away from key areas, today they seem ready to make arrests, as evidenced by the large deployment of officers to the open streets -- not behind barricades -- and use of blue dye in some water cannon jets, which could be used to stain and identify masked protesters.