Russia’s top diplomat condemned what he described as “an onslaught of belligerent revisionism” that threatens the international order in a rare personal criticism of U.S. President Donald Trump, reflecting growing tensions between the former Cold War enemies.

Russian Foreign Minister Sergei Lavrov lashed out at Trump’s policies in the Middle East, his withdrawal from the Iran nuclear deal and Paris climate treaty as well as his moves to ratchet up trade tensions in a speech Friday at the United Nations General Assembly.

And in an announcement certain to stoke U.S. concerns, Lavrov told reporters in New York later that Russia has already begun delivering advanced S-300 air-defense systems to Syria.

The annual gathering of world leaders has reinforced the divisions between Russia and the U.S. The two countries clashed over postwar plans for Syria, with Russia pushing the UN to help find funds for rebuilding the country, while the U.S. insists it should be overseeing a political transition away from Bashar al-Assad’s rule. Russia also joined forces with the European Union and China in a bid to safeguard trade with Iran from renewed U.S. sanctions.