U.S. Secretary of State Antony Blinken will visit Ukraine next week amid heightened tensions with Russia over a military buildup in the region.

CBS News reported Blinken confirmed the trip in an interview to be aired on its 60 Minutes program on May 2.

A Russian troop buildup in recent weeks near Ukraine’s border and in occupied Crimea has raised concerns of an escalation of the conflict in Kyiv and in the West. But on April 23, Moscow announced that it had started pulling back its forces.

“There are more forces amassed on the border with Ukraine than any time since 2014, when Russia actually invaded,” Blinken said in an excerpt of the interview released by CBS.

Moscow said its troop buildup was a military drill and dismissed Western concerns as involvement in a sovereign manner.

Blinken said the United States does not know Russian President Vladimir Putin’s intentions.

“There are any number of things that he could do or choose not to do. What we have seen in the last few days is apparently a decision to pull back some of those forces and we’ve seen some of them, in fact, start to pull back,” Blinken said in the CBS interview.

The developments come against the backdrop of a cease-fire from last summer unravelling, with deadly clashes increasing between Ukrainian forces and Russia-backed separatists in a war that has killed more than 13,000 people since April 2014.

Around 30 Ukrainian soldiers have been killed since the start of the year compared with 50 in all of last year, while the separatists have reported at least 20 military deaths.