Russian President Vladimir Putin has claimed “success” in Mariupol but ordered his forces not to storm the site where the last pocket of Ukrainian resistance in the besieged port city is holding out.

In a rare televised meeting at the Kremlin on Thursday, Defense Minister Sergei Shoigu told Putin that the sprawling Azovstal steel plant was “securely blocked” while the rest of the strategically vital city was “liberated.”

Putin said that rather than risk Russian soldiers’ lives by launching a final ground assault on the remaining Ukrainian stronghold in the city, they should instead blockade it “so that not even a fly comes through.”

Ukrainian forces have held out under weeks of heavy bombardment that have decimated much of the city and prompted international condemnation of Moscow’s tactics. A commander in Mariupol on Wednesday issued a video plea for help, saying his troops were facing their final days. Kyiv has been desperately seeking ways to evacuate the soldiers and thousands of civilians still trapped in the city without much food or aid.