The Lockeed Martin's THAAD missile defense system is seen during the 3rd annual Made in America product showcase at the White House in Washington D.C., the United States, July 15, 2019. (Xinhua/Ting Shen)

The Russian authorities said that the U.S. missile test was being prepared long before August 2 when the INF Treaty officially ceased to operate.

MOSCOW, Aug. 20 (Xinhua) -- Washington's latest test of a missile previously banned by the Intermediate-Range Nuclear Forces (INF) Treaty proves that it started preparing to pull out of the arms control treaty long in advance, Russian Foreign Minister Sergei Lavrov said Tuesday.

"This was being prepared for a long time, long before August 2, when the legal obligations of the parties formally expired under the INF Treaty," Lavrov told reporters at the opening of a World War II exhibition, according to a transcript of the foreign ministry.

The diplomat recalled that U.S. National Security Adviser John Bolton said in October that U.S. President Donald Trump had decided to withdraw from the treaty.

"Apparently, at that time, and maybe even earlier, they began to prepare the tests which violate the parameters contained in the INF Treaty," Lavrov said.

Earlier in the day, Kremlin spokesman Dmitry Peskov said that "such tests cannot be prepared in a few weeks or even months," suggesting that the United States has been nurturing plans to develop these weapons for a long time.

The test proves that Washington -- not Moscow -- is responsible for burying this landmark document, Peskov said.

On Monday, the Pentagon said in a statement that the United States tested a new ground-based conventional cruise missile which can hit a target more than 500 km (310 miles) from the launch site.

The INF Treaty, which had banned land-based missiles with a range of 500 km (310 miles) to 5,500 km (3,410 miles), ceased to operate on Aug. 2 after the United States and Russia accused each other of violating it.