US decision to send long-range missiles to Kyiv a grave mistake - Russia's envoy

(Reuters) - Washington's decision to send long-range ATACMS missiles to Ukraine was a grave mistake that will have serious consequences, Russia's ambassador to the U.S. said on Wednesday, after Kyiv said it used the weapons for the first time.

"The consequences of this step, which was deliberately hidden from the public, will be of the most serious nature," , Ambassador Anatoly Antonov said on the Telegram messaging app.

After media reports that the U.S. secretly provided Ukraine with ATACMS (Army Tactical Missile Systems) in recent days, the White House confirmed on Tuesday that it had recently provided Kyiv with a type of ATACMS capable of hitting targets up to 165 km (102 miles) away.

Ukraine's President Volodymyr Zelenskiy also confirmed his forces used the ATACMS after his military reported on Tuesday striking two air bases in Ukrainian territory now controlled by Russia.

Ukrainian Special Forces said nine helicopters, an air defence missile launcher, runways and other equipment had been destroyed near Luhansk in Ukraine's east and in Berdiansk in the south, on the Sea of Azov, both under Russian control.

Ukraine had repeatedly asked the U.S. administration for the ATACMS and pledged not to use inside Russia's territory. It said the powerful weapons would alter the course of the 20-month-old war that Russia launched.

It remains to be seen how much of an advantage the missile system will give Ukraine, but Kyiv officials have said they will push Russia to move its key air assets far back from the front lines.

The Kremlin has said U.S. supplies of ATACMS missiles and Abrams tanks to Ukraine would not change the situation on the battlefield.

"Washington is consistently pursuing a policy of completely curtailing bilateral relations," Antonov said. "The United States continues to push for a direct conflict between NATO and Russia.

(Reporting by Lidia Kelly in Melbourne; Editing by Christopher Cushing and Lincoln Feast)