Russia threatens Ukraine after shell crosses border

Russia threatened Ukraine on July 13 with "irreversible consequences" after a man was killed by a shell fired across the border from Ukraine, an incident Moscow described in warlike terms as aggression that must be met with a response.

Although both sides have reported cross-border shootings in the past, it appears to be the first time Moscow has reported fatalities on its side of the border in the three-month conflict which has killed hundreds of people in Ukraine.

Kiev called the accusation its forces had fired across the border "total nonsense" and suggested the attack could have been the work of rebels trying to provoke Moscow to intervene on their behalf. The rebels denied they were responsible.

Inside Ukraine, combat has intensified dramatically since a rebel missile attack that killed dozens of government troops on Friday. Local officials said on Sunday 18 people were killed in shooting incidents in the two main rebel-held cities.

Russia's Interfax news agency said fierce fighting had broken out on the outskirts of rebel-controlled Luhansk, a city near the border with Russia, and the Ukrainian army had attacked with a force of 70 tanks.

Kiev said it had bombarded a convoy of 100 armoured vehicles and trucks that had crossed into Ukraine carrying in rebel fighters from Russia. It also said seven of its troops had been killed in attacks.

Moscow's bellicose response to the cross-border shelling raises the renewed prospect of overt Russian intervention, after weeks in which President Vladimir Putin had appeared intent on disengaging, pulling back tens of thousands of troops he had massed at the frontier.

Russia sent Ukraine a note of protest describing the incident as "an aggressive act by the...