An American-Israeli hacker has been jailed for 10 years by a Tel Aviv youth court in connection to hundreds of fake bomb threats to planes and Jewish centres, including one that led to fighter jets being scrambled in Europe to intercept an airliner.

Michael Kadar was found guilty in June of about 2,000 hoaxes between 2015 and 2017 that were so extensive that they contributed to rising fears of antisemitism in the United States.

While Israel has never named the the 20-year-old as he was a teenager when he committed the crimes, the US justice department, which jointly investigated his case with Israeli police, identified him in charging documents last year.

Known in Israel as the “JCC bomb hoaxer” for his focus on Jewish community centres, Kadar’s targets also included airports, malls, police stations and hospitals from the US to Australia.

His defence said he had autism and a brain tumour, and should not be regarded as legally competent. However, the sentence handed down on Thursday was three years longer than the seven the prosecution had requested.

The Tel Aviv district youth court ruling acknowledged that he was autistic but stated that he “has a high IQ and understands his deeds very well”. The ruling added: “If not for his medical condition, the defendant would have received a much longer sentence.”

According to US court documents, Kadar made at least 245 threatening telephone calls involving bomb and active shooter threats in the first two months of 2017, a significant portion of which targeted Jewish institutions, such as the Anti-Defamation League.

His calls contained graphic descriptions of fake impending violence to the facilities, and particularly to children, with many resulting in evacuations or lockdowns, the documents said.

In one call to a Jewish preschool in Florida, Kadar warned a bomb “would blow off the children’s heads, and two dozen children would be slaughtered”, as he claimed to be in a car near the school with the detonator in hand. Sometimes Kadar threatened to kill children he claimed to be holding hostage.

Separately, he was charged with attempts to blackmail Ernesto Lopez, a Delaware state senator, with incriminations on the internet, and threatening to kidnap and kill the children of a former Pentagon official.

Kadar worked internationally. In June 2015, six people were injured at a Canadian airport when a threat he called in forced passengers to disembark on emergency slides in a panic. The next year, following a bomb threat later attributed to him, Switzerland and France scrambled fighter jets to accompany a plane operated by Israel’s national carrier, El Al, as it passed through their airspace.

Another was against a plane flying the Boston Celtics US basketball team, and one forced a Virgin Atlantic aircraft to dump eight tonnes of fuel before landing to lessen the potential fire risk from an explosion.

Kadar masked his online identity, hiding his IP address and altering his voice using audio-changing technology on the calls. Israeli authorities, working with the FBI, tracked him to a the coastal city of Ashkelon last year.

Reports in the Israeli media said Kadar took payments for some of the school bomb threats from students who wanted exams postponed.

If the US seeks to conduct its own prosecution in national courts it would require a successful extradition request, although it is not clear if that will happen.