The UN said the latest reports from Ukraine show the need for "immediate de-escalation of the conflict."
The UN spokesperson said the organisation was not able to verify reports of Ukrainian shelling of Russian armoured convoy, which Ukraine said crossed border into Ukraine during the night.
Russia has denied that its troops entered its neighbour's territory.
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It will be increasingly humid and thundery with highs of 30C or more today.
Holidaymakers in Tunisia are determined not to be beaten. But, as Neil Connery writes, it won't be easy to escape the shock of the massacre.
Drink lots of water, stay out of the sun during the middle of the day, and take particular care of vulnerable people.