Romania accused Russia of a “serious and irresponsible escalation” after a drone entered its airspace early on Friday and crashed into an apartment building, injuring two people.It was the most serious such incident for the eastern flank Nato member since Moscow invaded neighbouring Ukraine more than four years ago.Romania’s defense ministry said radar systems tracked the drone from its border with Ukraine to the eastern town of Galati, where it hit the rooftop of an apartment building, according to a statement on its website. The crash sparked a fire and injured two people. The building was evacuated and the entire area was put on alert.Two F-16 fighter jets were scrambled to track several drones flying near the border with Ukraine and the pilots had clearance to engage with the aerial targets, the ministry said. Romania informed its allies in Nato and asked for an accelerated transfer of anti-drone capabilities.“This incident represents a serious and irresponsible escalation by the Russian Federation,” Romanian foreign ministry said in a statement on Friday. “Romania will take the necessary diplomatic measures to respond to this serious violation of international law and its airspace.”Nato spokesperson said in a post on X: “We condemn Russia’s recklessness, and Nato will continue to strengthen our defences against all threats, including drones.” Nato secretary general Mark Rutte is in touch with the Romanian government over the issue.European Commission president Ursula von der Leyen said the drone incident showed that Russia’s war has “crossed yet another line”.Earlier this week she called for unified alert systems and improved cross-border co-ordination after a string of Ukrainian drone incursions into Baltic airspace exposed gaps in Europe’s defencesRomania and other Nato members on the eastern flank have seen an increase in airspace violation from Russia’s conflict. Earlier this month, Estonia shot down a stray Ukrainian drone, while Lithuanian leadership was forced to take shelter during an alert in Vilnius.Successive Romanian governments have faced criticism over their response to drone breaches. The authorities have avoided shooting them down, saying a military response requires careful assessment to avoid unnecessary escalation and risk to the population.Critics, including former president Traian Basescu, said that failing to intercept unauthorised drones may create security risks and undermine public confidence in the country’s ability to protect its airspace.The debate reflects the broader challenge faced by many countries in balancing national defence concerns with legal, diplomatic, and operational considerations when responding to aerial incursions and Russia’s more aggressive testing of Nato’s borders.It’s also having political ramifications. In Latvia, the controversy over allegedly insufficient response to incursions by Ukrainian drones led to a collapse of the ruling alliance earlier this month. – Bloomberg