U.K. intelligence also concluded that Russia's offensive in the Donbas had "lost momentum and fallen significantly behind schedule" and that units engaged in the offensive were suffering from "low morale and reduced combat effectiveness."
Russian forces, the assessment concluded, are "unlikely to dramatically accelerate [their] rate of advance over the next 30 days."
While Ukrainian forces held the line and even launched a new counteroffensive near Russian-held Izium, the international community continued to close ranks against Russia.
Finnish President Sauli Niinistö and Prime Minister Sanna Marin formally announced on Sunday that Finland is seeking to join NATO. Parliament will vote to ratify the membership proposal on Monday and could submit a formal application the following day.
Sweden's governing Social Democrats are likely to drop their longstanding opposition to joining NATO at a meeting on Sunday, with an application to follow soon after.