BANGKOK — More than two dozen people were injured in twin explosions at an antigovernment demonstration in Bangkok on Sunday, a further escalation of violence in Thailand’s protracted political crisis.

Officials with Bangkok’s emergency services said at least 28 people were wounded. The blasts, which occurred at a major intersection that protesters have blocked for the past week, followed a grenade attack on Friday that killed one protester and wounded more than 35. On Saturday, another protester was shot and seriously wounded.

The daily violence has not reached the level seen during the political upheaval in 2010, when a few neighborhoods in Bangkok turned into something resembling a war zone.

But once again, weapons of war are being used on the streets of this otherwise cosmopolitan city and tourist hub, underscoring the depth and complexity of the country’s eight-year power struggle. Thailand is divided between north and south and between the supporters and the detractors of a political movement founded by Thaksin Shinawatra, a former prime minister ousted in a 2006 military coup. His sister Yingluck Shinawatra is the current prime minister.