White House national security adviser Jake Sullivan said Friday that U.S. intelligence agencies assess that Russian President Vladimir Putin still hasn’t made up his mind on whether to invade Ukraine but is giving "serious consideration" to doing so.

The assessment is consistent from last week, when President Biden spoke with Putin and warned him Russia would face economic consequences if it launched a military invasion of its neighbor.

“The current assessment of the U.S. government is that he has not yet made a decision,” Sullivan told an audience at the Council on Foreign Relations. “I have high confidence in our capacity to see what has been a significant Russian military buildup in the vicinity of Ukraine and in Ukraine itself, in Crimea and other places.”

“I also think that the analysis that the intelligence community has laid out to indicate that the Russian government is giving serious consideration and operational planning to such an exercise is well validated,” Sullivan continued. “It’s something that we’ve shared with allies and partners, and it has motivated them to join us in a very strong chorus of clear messaging around the massive consequences ... that would befall Russia should it choose to further invade Ukraine.”

Biden and Putin held a two-hour phone call last week, during which the American president communicated that there would be harsh economic consequences if Russia were to invade Ukraine. The conversations between Washington and Moscow on Ukraine have continued at lower levels over the past week. 

The U.S. warnings have not seemed to change Russia’s military buildup on the border with Ukraine, however. 

Biden has also pledged to send additional security assistance to Ukraine and beef up U.S. military presence in NATO’s eastern flank, though he has made clear that sending American troops into Ukraine is off the table.

Russia on Friday released draft documents demanding that NATO deny Ukraine membership in the alliance and reduce military deployments to central and eastern Europe.

Sullivan said the U.S. is prepared to engage with Russia regarding its concerns with NATO but said officials would coordinate closely with allies.  

“We’re going to put on the table our concern with Russian activities that we believe harm our interests and values,” Sullivan said. “We can make progress in some areas. in other areas we’re just going to have to disagree.”