Israel conducted airstrikes on the central Gaza Strip early on Thursday, according to journalists and witnesses, hours after the military said it intercepted a rocket fired from the Palestinian territory.

New rounds of rockets were fired from Gaza after these strikes, and fresh explosions could be heard from Gaza City about 3.15am local time, Agence France-Presse journalists reported.

In a statement issued at 2.41am, the Israeli army confirmed it was “striking in the Gaza Strip”.

According to local security sources and witnesses, the first strikes – at least seven – hit a training centre of the Ezzedine al-Qassam Brigades, the armed wing of the Palestinian Islamist movement Hamas. The centre is located in al-Maghazi refugee camp in the central Gaza Strip.

A second round of airstrikes by the Israeli army targeted the al-Qassam Brigades’ training centre south-west of Gaza City, according to local security sources.

After the first airstrike, an AFP reporter saw two more rockets fired into Israel from the Gaza Strip, and witnesses said several more rockets were fired from various locations.

A statement by the Israeli army said fighter jets had “struck a production site for raw chemical material production, preservation and storage along with a weapon manufacturing site” belonging to Hamas.

The strikes came “in response to the rocket launch from the Gaza Strip into Israel earlier” on Wednesday.

Gaza, densely populated with 2.3 million people, has been under an Israeli blockade since Hamas took power in 2007.

The Popular Front for the Liberation of Palestine (PFLP), a secular Palestinian armed group, said it had launched rocket salvos at Israel early on Thursday in response to the airstrikes and the “systematic aggression” against Palestinian prisoners in Israeli jails.

Earlier on Wednesday, the firebrand Israeli national security minister, Itamar Ben-Gvir, who oversees prisons, said he would push ahead with plans to toughen conditions for Palestinian inmates in Israeli jails.

He claimed the recent bout of rocket fire was due to his decision to close two makeshift bakeries operated by Palestinian militants in Israeli prisons and called the bakeries part of the unwarranted “benefits” that “terrorists” were subject to.

“The launch from Gaza won’t weaken my resolve to continue working toward changing the summer camp conditions of murderous terrorists,” the minister said.

The Israeli prison service said the problems started last Friday when it placed dozens of Palestinian prisoners in solitary confinement after they celebrated the deadly Palestinian attack outside a synagogue in east Jerusalem.

Earlier this week, the US secretary of state, Antony Blinken, finished his Middle East tour with no breakthrough in reducing tensions between Israelis and Palestinians, saying that it was “fundamentally up to them” to end the violence after days of bloodshed.

Blinken said he had heard “deep concern about the current trajectory” during meetings in Israel and the occupied West Bank but, beyond calling for a “de-escalation”, he offered no new US initiative.

An Israeli operation in the Jenin refugee camp last week, one of its deadliest raids in the West Bank for decades, killed 10 Palestinians, mostly gunmen but also two civilians, including a 61-year-old woman. The next day, a Palestinian gunman killed seven Israelis outside a synagogue in East Jerusalem in the worst such attack in recent memory.

Almost two dozen people have been killed over the past week, as heightened tensions have led to retaliatory attacks, including shootings, targeting Israelis and Palestinians.

Agence France-Presse, Reuters and the Associated Press contributed to this report