Ukrainian President Volodymyr Zelenskyy promised retaliation for a Russian missile attack on Saturday that killed seven people including a six-year-old girl.

The missile hit the city center of Chernihiv, 150 kilometers north of Kyiv. The attack was carried out on a religious Orthodox festival and injured 144 people, including 15 children, Zelenskyy said in a statement early Sunday morning.

“Our soldiers will respond to Russia for this terrorist attack,” Zelenskyy said. “Respond tangibly.”

Zelenskyy is on a mini-tour this weekend to shore up military supplies from allies so Ukraine can continue its counteroffensive against Russia’s invasion. The Ukrainian leader was in Sweden on Saturday for talks about Gripen fighter aircraft and CV90 combat vehicles.

On Sunday, he traveled to the Netherlands, which said on Friday that the U.S. had given its approval for Dutch and Danish deliveries of F-16 fighter jets to Kyiv’s air force. Zelenskyy is meeting with Dutch Prime Minister Mark Rutte at a military air base in the southern city of Eindhoven, the AP reported. 

Following the Chernihiv attack, Russia said it had thwarted a Ukrainian drone assault on Moscow and the surrounding region, the second such incident in two days as Kyiv presses ahead with a counteroffensive.

“The air defense forces on duty discovered an unmanned aerial vehicle flying over the territory of the Stupinsky district of the Moscow region in the direction of the city of Moscow,” the Russian Ministry of Defense said in a statement. “The UAV was suppressed by electronic warfare and, having lost control, crashed in a deserted area. There were no casualties or damage.”