Sullivan answered questions from reporters a number of topics.
Concern that Russia may use chemical weapons was an “important topic of conversation” during Biden’s visit to Europe. Biden vowed to respond “in kind” if Russia uses chemical weapons in Ukraine.
Pressed on what that means, as chemical weapons are illegal under international law and Biden has repeatedly said the US would not send troops to fight Russia in Ukraine, Sullivan said it was an issue being discussed and prepared for both militarily and diplomatically as well as among allied leaders.
“We are working through contingency planning for a range of different scenarios,” he said. “It is difficult to give precision to these kinds of hypotheticals because of course, the form of use, the location of use, the context of use, all have a bearing on the specificity of the response. But in broad terms, I believe that there is convergence around the fundamental nature of how the alliance would respond to these issues.”
He also told reporters that the US does not believe China has granted Russia’s request for military aid.
“We have not seen the Chinese move forward with the provision of military equipment to Russia, but it’s something we continue to watch every day,” he said.
Asked whether the president expected to discuss a Polish proposal to send international peacekeepers into Ukraine, Sullivan said he wasn’t sure if the Polish president would raise that with Biden during their meeting and said the US needed more information before it responded.
He also said there is “no update” on Ukraine’s request for more warplanes, after the US rejected a proposal from Poland to transfer Russian-made MiG fighter planes from a US base in Germany to Ukraine out of concern that it might escalate the conflict with Russia.
Asked about how Biden views his trip to Europe, Sullivan emphasized a point Biden stressed in his remarks on Thursday: that unity will take work over time.
“Part of the reason that he decided that we needed to do this is because the early weeks unity can be carried forward by momentum and inertia and adrenaline,” Sullivan said. “But this could go on for some time, and to sustain that unity as costs rise, as the tragedy unfolds, that’s hard work. And the president wanted to get everybody together to say, ‘we’ve got to do that work.’ …It takes an American president coming over to really try to drive this forward.”