Mexico’s government pledged Monday to take control of a violent western state after days of fighting between masked vigilantes and members of one of the country’s most powerful drug cartels, Reuters reports.

Since late 2013, vigilante groups in the state of Michoacan have moved deeper into Knights Templar cartel-controlled territory, and now they are converging on Apatzingan, considered one of the gang’s main strongholds. However, the vigilantes’ movement has raised the risk of a bloody urban battle in the city, and Interior Minister Miguel Angel Osorio Chong urged the groups to withdraw from the battleground so federal forces could take over, the article says.

Analysts warn that any siege on Apatzingan by the vigilante groups could spark a much larger and more unpredictable urban conflict, and that the government may have waited too long already to try to contain the growing vigilante movement.