JERUSALEM — It was a particularly horrifying sight, even for the medical volunteers who have seen scores of terrorist attacks here: young students of no more than 17 or 18 slumped over their books, covered in blood.

This was the scene last night at the first terrorist attack in Jerusalem in nearly four years, when a Palestinian Arab entered the 76-year-old Yeshiva Mercaz HaRav Kook, walked into the library, and killed eight students.

“I was upstairs on the second floor, and I heard sounds like shooting, but we didn’t know what it was because it’s going to be Purim soon,” a student at the yeshiva and native of the Ginat Shomron settlement, Eric Katanov, told The New York Sun. “We thought it was firecrackers, but after one minute, I said, ‘No, it’s an attack, that’s it,'” Mr. Katanov, 23, said.

According to Mr. Katanov, the school is at “the heart of the settlement ideology.”

“I was in a class that finished at 8:25, and we were getting ready to go home. All of a sudden we heard all these volleys of shots,” a student in the school’s rabbinical training program for middle-age men, Dr. Joel Luber, said.

Dr. Luber, a Philadelphia native who lives in the settlement of Alon Shvut, said the yeshiva has not had a security guard outside for more than a year.

The terrorist, identified as a resident of East Jerusalem, opened fire at the building’s entrance and in the library, only a few yards away, an Israel Police spokesman, Chief Inspector Micky Rosenfeld, said.

Mr. Rosenfeld said one terrorist was shot and killed, and a number of bodies were scattered at the yeshiva entrance, as well as on the upper floors. Police quickly searched the building to eliminate the possibility of another attack. The director general of the Jerusalem municipality, Yair Maayan, said the incident does not necessarily signal a new wave of attacks. “Jerusalem is very safe, safer than most places of the world,” he said, adding that yesterday’s attack was the first in the Kiryat Moshe quarter, home to several other religious seminaries. The incident was also the first to directly target a yeshiva. “The last couple of years have been quiet,” a native of Brooklyn and student at the nearby Mir Yeshiva, Chaim Cohen, 21, said. “This is the first incident to really strike home, smack in the middle of a yeshiva. People are worried that it’s so local.”

Previous attacks in the city have centered on open, commercial areas like restaurants or buses. “I’ve seen many attacks from volunteering, but in the past they’ve been on public streets, where it’s much easier to breach the security,” said a volunteer for a medical response agency, United Hatzolah of Israel, who was not allowed to report his name. “To actually get so far into the city into the yeshiva, it’s a sign [the terrorists] are making headway.”