MOSCOW  Violent protests over political grievances and mounting economic woes shook the Latvian capital, Riga, late Tuesday, leaving around 25 people injured and leading to 106 arrests.

In the wake of the demonstrations, President Valdis Zatlers threatened Wednesday to call for a referendum that would allow voters to dissolve Parliament, saying trust in the government, including in its ability to deal with growing economic problems, had “collapsed catastrophically.”

For years, Latvia boasted of double-digit economic growth rates, but it has been shaken by the global economic downturn. Its central bank has spent a fifth of its reserves to guard against a steep devaluation of its currency, the lat, and experts expect a 5 percent contraction of the country’s gross domestic product in 2009. Salaries are expected to fall substantially, and unemployment is expected to rise.

The violence followed days of clashes in Greece last month over a number of issues, including economic stagnation and rising poverty as well as widespread corruption and a troubled education system. In Bulgaria on Wednesday, separate riots broke out in the capital, Sofia, after more than 2,000 people  including students, farmers and environmental activists  demonstrated in front of Parliament over economic conditions, Reuters reported.