The Trump administration is slow-walking $250 million in military assistance to Ukraine, annoying lawmakers and advocates who argue the funding is critical to keeping Russia at bay.

President Donald Trump asked his national security team to review the funding program, known as the Ukraine Security Assistance Initiative, in order to ensure the money is being used in the best interest of the United States, a senior administration official told POLITICO on Wednesday.

But the delays come amid questions over Trump’s approach to Russia, after a weekend in which the president repeatedly seemed to downplay Moscow’s military intervention in Ukraine and pushed for Russia to be reinstated into the Group of Seven, an annual gathering of the world’s largest advanced economies. The review is also occurring amid a broader internal debate over whether to try and halt or cut billions of dollars in foreign aid.

United States military aid to Ukraine has long been seen as a litmus test for how strongly the American government is pushing back against Moscow.

The Trump administration in 2017 approved lethal arms sales to Ukraine, taking a step the Obama administration had never done. The move was seen as a sign that Trump’s government was taking a hard-line approach to a revanchist Vladimir Putin despite the president’s public rhetoric flattering the Russian leader. Scaling back that assistance could expose Trump to allegations that his policies are favoring Moscow.