German Defense Minister Christine Lambrecht warned on Thursday against dismissing Russia’s nuclear threats in the Ukraine conflict.

The warning was issued by Lambrecht on the sidelines of a NATO defense ministers’ meeting in Brussels.

“It is critical that we take Russia’s threats very seriously and adapt accordingly,” Lambrecht said.

NATO ministers were scheduled to meet to discuss how to deal with Russian President Vladimir Putin’s threats. The nuclear planning group’s consultations and deliberations, however, would be kept private.

Lambrecht requested that it be understood that these discussions would take place in “internal, secret committees.”

“However, I can say that we are ready.” She continued.