(CNN) The United States has decided to certify a Russian aircraft to make a surveillance flight over the US under the Open Skies Treaty, a week after declining to do so.

Under the treaty, the member states are permitted to conduct unarmed surveillance flights over one another's territories. It "is designed to enhance mutual understanding and confidence by giving all participants, regardless of size, a direct role in gathering information through aerial imaging on military forces and activities of concern to them," according to the State Department.

In early September, experts from a number of the member states gathered in Russia for the certification event for Russia's Tu-214 Open Skies aircraft, a State Department official told CNN. The US declined to certify the aircraft at the time, citing ongoing discussions in Washington, according to the official.

However, the US reversed course and on Tuesday, "the United States informed all States Parties via formal treaty mechanisms that we will approve the certification of the Russian aircraft," the official said.

A date has not been set for the Russian flight, and neither country has any flights scheduled due to an "impasse at the Open Skies Consultative Commission that continues to delay the commencement of treaty flights in 2018," according to the State Department official, who did not elaborate on the reasons for the impasse. The US has said Russia is in violation of the Open Skies Treaty because they are not allowing flights over Kaliningrad, a Russian exclave between Lithuania and Poland where Moscow has a significant military footprint.

On Tuesday, Andrea Thompson, the under secretary of state for arms control and international security, told the Senate Foreign Relations Committee that "Russia remains unwilling to lift its illegitimate limits on the distance Open Skies Treaty parties can fly over the strategically sensitive region of Kaliningrad."

"In September 2017, we made clear our commitment to addressing Russia's continued noncompliance with the treaty when we established several reasonable, treaty-compliant measures designed to encourage Russia to resolve its violations," she said. "These measures are in effect and will impact any Russian flights over the United States; they will be reversed if Russia returns to full compliance."

This story has been updated.