President Vladimir Putin on Thursday ordered the Russian military to cancel plans to storm the Azovstal plant in the Ukrainian port city of Mariupol and said he wanted it to continue to be hermetically blockaded instead.

Putin gave the order to Sergei Shoigu, his defense minister, who had previously told Putin that more than 2,000 Ukrainian fighters were still holed up in the vast plant, which has a large underground component to it.

“I consider the proposed storming of the industrial zone unnecessary,” Putin told Shoigu in a televised meeting at the Kremlin. “I order you to cancel it.”

Putin said his decision not to storm the Azovstal plant was motivated by the desire to safeguard the lives of Russian soldiers.

“There is no need to climb into these catacombs and crawl underground through these industrial facilities,” he said. “Block off this industrial area so that a fly cannot not pass through.”

Putin also called on the remaining Ukrainian fighters in Azovstal who had not yet surrendered, saying Russia would treat them with respect and would provide medical assistance to those injured.

Russia sent tens of thousands of troops into Ukraine on Feb. 24 in what it called a special operation to degrade its southern neighbor’s military capabilities and root out people it called dangerous nationalists.

Ukrainian forces have mounted stiff resistance and the West has imposed sweeping sanctions on Russia in an effort to force it to withdraw its forces.