China warned the U.S. and Russia against exacerbating tensions around Ukraine

China told Washington that it hoped that all parties involved in the conflict over Ukraine would show calm and restraint and avoid an escalation of tensions in the region. Chinese Foreign Minister Wang Yi and U.S. Secretary of State Anthony Blinken held telephone talks late Wednesday night.

“We call on all sides to remain calm and refrain from taking steps that increase tensions and escalate the crisis,” Wang Yi said.

Wang Yi said one country’s security should not be sacrificed at the expense of the security of other states and that regional security cannot be achieved by strengthening or even expanding military blocs.

Blinken, for his part, said that “diplomacy and de-escalation are the responsible way forward.

Russia, which has been building up its military presence near Ukraine’s borders in recent months, demanded written guarantees from the U.S. that NATO would not expand eastward and that Ukraine would never be admitted into the military bloc.

In its written response to these demands on Wednesday, Washington reiterated that the current principles for admitting new members, as spelled out in the organization’s founding documents, would remain unchanged and refused to provide such guarantees to Moscow. The U.S. said it was ready to discuss arms control and other security issues with Russia.

“It’s up to Russia what the response will be. We are ready for any development,” Blinken said at a news conference Wednesday. “We prefer diplomacy,” he stressed.

Blinken said Washington’s response includes some proposals that U.S. diplomats talked about after talks with Russian officials. These include regulation of nuclear weapons, more transparency on military exercises and deployment of offensive weapons. The head of the State Department stressed that the document was coordinated with Ukraine and U.S. NATO allies.

“It’s not a formal negotiating document, it’s not direct proposals, it just sets out some thoughts on how we together – if they are serious – can strengthen collective security,” he said.