A NATO official, speaking on condition of anonymity, said the alliance’s “integrated air and missile defense tracked the flight path of an object which subsequently crashed in Zagreb.”
Earlier, Croatian President Zoran Milanovic had expressed concern at how “how a relatively unsophisticated drone flew for over an hour over NATO countries without being detected.”
Milanovic said "it is clear" it came from Ukraine. A statement issued by Croatia's government said the “pilotless military aircraft” entered Croatian airspace from neighboring Hungary at a speed of 700 kph (430 mph) and an altitude of 1,300 meters (4,300 feet).
“According to information I have so far, this flying object was Russian-manufactured, we are not sure whether it belongs to the Russian or Ukrainian army," Croatian Prime Minister Andrej Plenkovic said. “(It) arrived in Croatia from the direction of Hungary, and according to (Hungarian) Prime Minister Orban, it arrived to Hungary from the direction of Romania.”
The government said an official criminal investigation will be launched and NATO was informed. The crash means that the large drone flew for at least 350 miles (560 kilometers) over Croatia, Hungary and Romania, all members of the Western military alliance.
Military experts of The War Zone online magazine said the aircraft is likely a Soviet-era Tu-141 “Strizh” reconnaissance drone that must have severely malfunctioned. It said Ukraine is the only known current operator of the Tu-141, which has a wingspan of nearly 4 meters (12 feet) and weighs just over 6 tons.
Ukrainian defense ministry adviser Markian Lubkivskiy was quoted by Interfax news agency as denying the drone that crashed in Croatia was Ukrainian. He blamed Russia.
“This drone did not have Ukrainian markings,” he was quoted as saying. “There were red stars on it” — a symbol of the Russian military.
The Russian Embassy in Zagreb said that the drone was made in Ukraine and that the Russian forces stopped using Tu-141s since the breakup of the Soviet Union in 1991.
Croatian President Milanovic said the drone crashed in Zagreb after running out of fuel.
The Croatian defense minister and the army chief of staff both described the incident as “serious,” but said more details will be revealed after the ongoing investigation.
The two officials said at a news conference that Croatia responded last night with the closure of its airspace. They said they have been in contact with neighboring countries and NATO and refused to reveal whose drone it was.
“We can’t say at this moment whose it was. Those are relatively old-era flying objects that were used in the Soviet Union,” said Chief of Staff Adm. Robert Hranj.
Hungary’s foreign minister, Peter Szijjarto, said in a social media post Friday that Hungarian authorities were also investigating.
“According to the information currently available, the airspace of several NATO member states, including Hungary, was involved in the drone flight," he said.
Romania’s airspace surveillance system said it spotted on Thursday, March 10, a small aerial object which flew in the national airspace for under three minutes.
The aircraft entered from Ukraine around 23:23 and left Romanian airspace around 23:26, heading to Hungary, it said.
“The evolution of this aircraft object for a very short time in the national airspace, the high speed, the low flight altitude, associated with the rugged terrain and the weather conditions at that time, did not allow the use of other procedural measures to identify this aircraft in flight,” a statement said.
Zagreb mayor Tomislav Tomasevic said parts of the flying object are scattered in several locations. He said initial findings indicated it was an accident.
“No one was hurt and that is good fortune,” said Tomasevic. “It is a relatively big object. … It is amazing that no one was hurt.”
The Croatian police said they came to the scene of the explosion on the outskirts of Zagreb after calls from local citizens. They said they found a large crater and two parachutes in a wooded area. Some parked cars were damaged.
Photos from the scene show metal pieces of the wreckage scattered on the ground, a parachute hanging from tree branches and what seems to be a section of a wing. Police sealed off the area for investigation. The Tu-141 has parachutes for soft landings.
Witnesses quoted by the media said they first heard a large explosion that rocked the ground, then a foul smell of kerosene.
Dusan Stojanovic and Jovana Gec contributed from Belgrade, Serbia, Raf Casert from Brussels, Stephen McGrath from Bucharest, Romania, and Justin Spike from Budapest, Hungary.