BUENOS AIRES—The Argentine government deployed thousands of federal security forces across the country on Monday to stem a wave of looting by mobs that took advantage of an absence of police, who were on strike, authorities said.

Looters pillaged stores in a handful of provinces over the weekend, including Entre Ríos, on the border with Uruguay, where the governor said one man died after being electrocuted while stealing electronic goods, and 25 people were injured. Sporadic looting was also reported in Buenos Aires, Santa...