NATO Secretary-General Jens Stoltenberg on Friday reacted reservedly to a Chinese proposal for a ceasefire in Ukraine, saying Beijing did not have a lot of credibility as a mediator.

"China doesn't have much credibility because they have not been able to condemn the illegal invasion of Ukraine," he told reporters in Tallinn, adding Beijing had signed an agreement with Russian President Vladimir Putin only days before the invasion.

European Commission President Ursula von der Leyen said China had not shared a peace plan but some principles.

"You have to see them against a specific backdrop, and that is the backdrop that China has already taken sides by signing, for example, an unlimited friendship right before the invasion," she noted.

"So we will look at the principles, of course, but we will look at them against the backdrop that China has taken sides," she added. (Reporting by Bart Meijer and Reuters TV, writing by Sabine Siebold)