JERUSALEM — An Israeli teen who also holds U.S. citizenship was arrested in Israel on Thursday on suspicion of making dozens of hoax bomb threats against Jewish community centers in the United States and several other countries.

At a court hearing near Tel Aviv, the suspect’s defense attorney said the young man has a growth in his head that causes behavioral problems.

A police spokesman said the suspect, whose identity could not be reported under a court order, is 18, Jewish and a dual U.S.-Israeli national.

U.S. federal authorities have been investigating a surge of threats against Jewish organizations, including more than 100 bomb threats in separate waves over the past three months against Jewish community centers (JCCs) in dozens of states.

The incidents have stoked fears in the U.S. of a resurgence in anti-Semitism and forced the evacuation of many centers, including some with day care for young children.

Israeli police said FBI agents participated in the probe in Israel that led to Thursday’s arrest.

The suspect covered his face with his sweatshirt as he entered the court. The court extended his police detention for eight days.

“We believe he is responsible for the wave of calls, bomb threats, made to Jewish community centers in the United States,” the police spokesman said.

Galit Bash, the suspect’s defense attorney, said a medical condition was the root of problem.

“My client … suffers from a very serious medical problem, a problem that may affect his behavior, his ability to understand right and wrong,” his defense attorney told Reuters.

Israel’s Channel 10 news quoted her as telling the court he had a benign growth in his head.

Police said the suspect was responsible for a bomb threat against Delta Airlines flight 468 in January 2015 at New York’s John F. Kennedy airport.