(AP) — The Russian Embassy refused entry to Democratic Sen. Jeanne Shaheen, of New Hampshire, because she’s on a “black list” created in response to U.S. sanctions.

Shaheen and Republican Sens. Ron Johnson, of Wisconsin, and John Barrasso, of Wyoming, planned to travel to Russia in January, but the trip is now canceled.

Shaheen, who serves on the Foreign Relations Committee, has been an outspoken supporter of measures meant to counter Russia’s interference in U.S. elections.Related Content: Court upholds ban on Navalny running for Russian presidency

She learned this week that her Republican colleagues scuttled the trip because her visa request was rejected. Johnson, chairman of the Homeland Security and Governmental Affairs Committee, called Russia’s action “counterproductive to improving relations between our nations.”

In a statement, the Russian Embassy said Shaheen’s request was rejected because of the black list but that visas were issued to the other senators. The statement blamed Washington for creating “this situation” and urged Washington to renounce the sanctions imposed on Russia.Related Content: Putin voices hope for cooperation with US in letter to Trump

Shaheen has no intention on backing down.

“While she regrets the Kremlin decision … she vows to continue her work to hold the Russian government accountable for its actions that go against international norms and against the Russian people,” said spokesman Ryan Nickel.