KIEV, July 4 (Xinhua) -- Ukrainian President Volodymyr Zelensky said Friday that he had discussed Ukraine's air defense capabilities in a phone conversation with U.S. President Donald Trump.

They agreed that they would work together to strengthen protecting the skies of Ukraine, Zelensky said in a post on social media.

According to Zelensky, they also discussed defense industry capabilities and the possibilities of joint production.

The conversation also covered mutual procurement and investment, diplomatic situation, and Ukraine's cooperation with the United States and other international partners, Zelensky said.

The Trump administration had halted part of military aid to Ukraine following a review of U.S. own stockpiles, the White House and Pentagon confirmed Tuesday.

On Thursday, Trump said he did not make any progress on Iran and the Ukraine conflict during a phone call with his Russian counterpart Vladimir Putin. ■