In December 2021, senior U.S. military officials told lawmakers that they wanted to send a “few hundred” additional special operations personnel to Ukraine to provide military advice and training on unconventional warfare. At the time, Russia had amassed roughly 100,000 troops on the border with Ukraine, and concerns were growing in Washington and Europe about a broadening invasion, Politico reported.

But White House officials had concerns about the deployment and the troops were never sent, according to two people familiar with the two December briefings with lawmakers and congressional aides. They also said Defense Secretary Lloyd Austin planned to directly press President Joe Biden to approve the mission.

A senior military official told House lawmakers that the White House was concerned that sending the troops would escalate the already tense situation with Russia, according to the two people. A third congressional official said that a Pentagon official briefed the Senate Armed Services Committee that plans had been scrapped due to those concerns. The Biden administration hoped diplomacy might still work, and feared an influx of U.S. troops could scuttle those efforts.

The deliberations came at an extraordinarily challenging moment for the U.S. and Ukraine, and as American officials began sharing detailed intelligence with NATO allies about Russia’s planned invasion.

A White House spokesperson said “no such plans” for additional training missions “were ever presented” to the White House or the National Security Council.

A Defense Department official said Biden and the White House did not “cancel any planned training activities for Ukraine until U.S. forces were repositioned in February.”