Deadly border clashes between arch-foes Armenia and Azerbaijan entered a second day on Monday, as the EU, US and regional power broker Moscow urged restraint.

Three Azerbaijanis were killed on Sunday and one on Monday, oil-rich Baku's defense ministry said, adding that both sides were using artillery, mortars and tanks in the north part of their border.

The two former Soviet republics have been locked in a simmering conflict for decades over the Nagorny-Karabakh region.

AFP