Romania says a Russian drone has breached its airspace - the second Nato country to report such an incursion.

Romanian fighter jets were in the air monitoring a Russian attack in Ukraine on Saturday and were able to track the drone near Ukraine's southern border, the defence ministry said in a statement. 

Ukrainian President Volodymyr Zelensky said the incursion could not be a mistake - it was "an obvious expansion of the war by Russia". Moscow has not commented on the Romanian claims.