Slovakia approved a plan to send a fleet of 13 MiG-29 fighter jets to Ukraine, a day after Poland became the first NATO country to say it would send warplanes to Ukraine, writes The TIME.

“Promises must be kept and when Volodymyr Zelensky asked for more weapons incl. fighter jets, I said we’ll do our best”, - Prime Minister Eduard Heger tweeted, adding that he was glad other nations were doing the same.

Poland’s President Andrzej Duda announced that the country plans to give Ukraine about a dozen MiG-29 fighter jets. That announcement marked the first time an ally of Ukraine said it would provide warplanes in the fight against Russia. Poland and Slovakia’s back-to-back decisions will likely apply pressure on other Western nations to provide military aircraft amid pleas from Ukraine ahead of a likely counter-offensive this Spring.

So far, the U.S., U.K., and Germany have rejected Ukraine’s requests for fighter aircraft.