Ukrainian President Volodymyr Zelenskiy called for a faster buildup of major defensive lines amid Kyiv’s stalled counteroffensive and concerns that Russia could attempt to take more territory.

Zelenskiy urged greater speed and efficiency in building defenses in a video statement on Telegram after a meeting with key military and security officials Tuesday evening. He encouraged local communities to pitch in and pledged to make money available for the effort.

“Our country will definitely have enough mines and concrete,” he said. He didn’t provide details on where the fortifications would be built or how extensive they might be.

Ukraine’s counteroffensive stalled over the past months as Kyiv’s troops became bogged down trying to penetrate thick lines of defense built by Russia that include minefields and trench systems stretching for miles. Russian President Vladimir Putin has been keeping up the military pressure by sending more soldiers to the frontlines despite heavy casualties.

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The fighting may again expand beyond the east and south of Ukraine if Russia continues to boost its weapons production and improve military technologies with the help of its allies, Serhii Nayev, commander of the United Forces of the Armed Forces of Ukraine, told ABC News in an interview last weekend.

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Zelenskiy discussed defensive operations in Odesa and the Black Sea grain corridor on Wednesday as he visited troops deployed in the southern region.