Russian President Vladimir Putin said the terms of the ceasefire need to be worked out, including a mechanism to control possible breaches of the truce.
The top U.S. military officer said the recent North Korean and Russian summit means Pyongyang will probably provide Russia Soviet-era 152 mm artillery.
The crash raises questions about the future of Yevgeny Prigozhin’s private army, which fought alongside Russian troops in Ukraine before his June uprising.