President Sergio Mattarella warned that the situation risks spiralling out of control after Poland said its airspace had been violated by Russian drones overnight, describing the incident as "extremely serious" as he spoke in Ljubljana during the first leg of a visit to Slovenia.

"What creates alarm is that we are moving on a ridge from which we can slide into an abyss of uncontrolled violence," he said.

"What is happening in Ukraine is also accentuated by the Kremlin's threatening statements to European countries, which are an alarm-inducing element.

"The risk of sliding into a conflict of unimaginable and uncontrollable dimensions is extremely high." The head of State also criticised Israel's air strikes on Qatari capital Doha targeting Hamas's political leaders on Tuesday.

"Equal concern to what happened in Poland is incurred by what happened in Qatar, because it is unacceptable that the sovereignty of a country should be violated," he said.