German Chancellor Angela Merkel pledged to bolster internal security after violent riots at the G20 summit in Hamburg. The number of people working with the security authorities will be increased, Merkel said on Monday during a visit to the summer campus of the CSU country group in the Franconian monastery of Banz.

About 20,000 police struggled to contain several hundred demonstrators who torched cars, looted shops and hurled Molotov cocktails and stones during the July 7-8 summit. Police said almost 500 officers were injured during the protests, with 186 people arrested and 225 taken into custody.

The violence has angered Germans and raised awkward questions for Chancellor Angela Merkel less than three months before an election. Some commentators have criticized Merkel's choice of Hamburg, a seaport with a strong radical leftist tradition, to host the meeting, saying her desire to demonstrate her commitment to freedom of speech had backfired.

Merkel has condemned the actions of the rioters and insisted that victims of the protests receive compensation from the state. Hamburg retailers have demanded 18 million euros in damages from the protests. Inner-city shop owners made the request in a letter written to Hamburg Mayor Olaf Scholz after grocery markets and storefronts were plundered and badly damaged in the three days of violence, public broadcaster NDR 90.3 reported yesterday. To cover revenues lost during the demonstrations, the retail traders have demanded two additional Sunday shopping days during the crucial build-up to Christmas in December. Under German trade laws, shops are open for a set number of Sundays each year.