Ratcheting up a conflict with retailers of basic goods, President Nicolás Maduro on Friday ordered the government takeover of a supermarket chain that officials have accused of hoarding products as part of an “economic war” against his government. Mr. Maduro did not name the company, which he said had 35 medium-size stores in seven states, but it was clear that he was referring to the Día a Día chain. The stores are generally located in lower-middle-class or poor neighborhoods. Promising to use an “iron fist” in tackling economic problems, Mr. Maduro said the chain, which had a warehouse full of cooking oil and other items, was “making war on the people” and would be taken over by a government supermarket network known as Pdval. Venezuela has been hit hard by the drop in the price of oil, its only major export, and shortages and long lines at stores are common. Also on Friday, the government filed criminal charges against a manager of the supermarket chain, accusing him of destabilizing the economy. It filed similar charges this week against two executives of the country’s largest pharmacy chain, Farmatodo.