The overnight attacks -- which Israel's army confirmed in a statement at 02:41 am (0041 GMT) -- come hours after the army intercepted a rocket fired from the Palestinian territory.

Emergency services reported no immediate casualties on either side.

According to local security sources and witnesses, the first round of 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 in the Al-Maghazi refugee camp in the central Gaza Strip.

Another round of air strikes hit the al-Qassam Brigades' training centre southwest of Gaza City.

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" Wednesday.

After the strikes, AFP reporters and witnesses saw new rounds of rockets fired from Gaza, and fresh explosions could be heard from Gaza City around 3:15 am (0115 GMT).

The unrest comes after cross-border rocket fire from the Gaza Strip last week in retaliation to a deadly Israeli raid in the occupied West Bank, and a shooting attack outside a synagogue in annexed east Jerusalem on Friday that killed seven civilians.

That attack on the Jewish Sabbath was the deadliest targeting Israeli civilians in more than a decade and was celebrated by many Palestinians in Gaza and across the West Bank, where bloodshed is also rising.

Last week, Israeli forces killed 10 people from the Jenin refugee camp in their deadliest raid in the West Bank in nearly two decades.

Israel said Islamic Jihad militants were the target of the operation.

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 -- claimed Thursday after the air strikes to have carried out "a barrage of rockets... in response to the Zionist aggression on the Gaza Strip".

Warning sirens sounded in Sderot, a town in southern Israel close to the Gaza Strip, according to the army.

- Jericho 'seige' -

Earlier Wednesday, firebrand Israeli National Security Minister Itamar Ben-Gvir said the recent bout of rocket fire was due to his decision to close two makeshift bakeries operated by Palestinian militants in Israeli prisons.

He 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 escalating violence has affected much of the West Bank, with 2022 the deadliest year there since the United Nations started tracking fatalities in the occupied territory in 2005.

Some 235 people died in the Israeli-Palestinian conflict last year, with nearly 90 percent of the fatalities on the Palestinian side, according to AFP figures.

In January alone, Israeli forces killed 35 Palestinians, including attackers, militants and civilians, while the Friday attack in east Jerusalem killed six Israelis, including a child, and one Ukrainian.

The regional Palestinian governor on Wednesday accused Israel of putting Jericho -- a tourist destination near Jerusalem in the West Bank -- under "siege" after a Saturday shooting at a restaurant, which had no casualties.

"This is the fifth day of the siege on Jericho," governor Jihad Abu al-Assal told AFP.

Israel's army told AFP it had boosted its forces in the area and "inspections were increased at the city's entrances and exits".

An AFP correspondent said cars were backed up at entrances to the city, with checks to get in and out of the city often taking hours.

- 'Shrinking horizon of hope' -

During a recent visit to the region to meet Israeli and Palestinian leaders, US Secretary of State Antony Blinken called for both sides to take "urgent steps" to restore calm.

Washington has no contact with Hamas, which it considers a terrorist organisation.

The Islamic Jihad said it would send a delegation led by the militant group's leader Ziad al-Nakhala to Cairo on Thursday at Egypt's invitation.

The delegation would meet with head of Egypt's intelligence service to discuss "how to restore calm, especially after the last escalation, including the aggressions against prisoners", said Daoud Shihab, a senior Islamic Jihad member in Gaza.