At least 40 Palestinians have been killed in Israeli airstrikes on a tent encampment designated as a humanitarian zone in Khan Younis, Gaza officials said early on Tuesday, in what the Israeli military said was an attack on a Hamas command centre.

Gaza civil defence officials told Agence France-Presse and the BBC that as well as the 40 people killed in the attack inside the Al-Mawasi camp, a further 60 were injured and transferred to local hospitals.

Residents and medics said the tent encampment in the al-Mawasi area was struck by at least four missiles. The camp is crowded with displaced Palestinians who have fled from elsewhere in the enclave.

The Gaza civil emergency service said at least 20 tents caught on fire, and missiles caused craters as deep as nine metres (30ft). There was no immediate comment from the Gaza health ministry, which compiles casualty figures.

“Our teams are still moving out martyrs and wounded from the targeted area. It looks like a new Israeli massacre,” a Gaza civil emergency official said.

The Israel Defense Forces (IDF) said it “struck significant Hamas terrorists who were operating within a command and control centre embedded inside the humanitarian area in Khan Younis.

“The terrorists advanced and carried out terror attacks against IDF troops and the state of Israel,” the statement said.

Hamas denied its fighters were present at the scene of the strike, saying in a statement on Telegram: “The occupation’s allegations of the presence of resistance fighters are a blatant lie.”

At the scene of the attack, ambulances raced back and forth to a nearby hospital, while Israeli jets could still be heard overhead, residents said.

Nearly all of Gaza’s 2.3 million people have been forced from their homes at least once, and some have had to flee as many as 10 times.

Several hundred thousand people have packed into al-Mawasi since the beginning of the conflict despite minimal provision there of basic services. Last month, humanitarian officials confirmed that overcrowding there was dissuading those given evacuation orders by the IDF from leaving, despite the dangers of remaining.

There have been a number of deadly attacks on the camp since the conflict broke out last year.

The war was triggered on 7 October when Hamas attacked Israel, killing 1,200 people and taking about 250 hostages.

Israel’s subsequent assault on Gaza has killed more than 40,900 Palestinians, according to the territory’s health ministry. Thousands more are believed to be buried under the rubble while thousands more have died of the indirect consequences of the war and tens of thousands have been injured.

The two warring sides each blame the other for a failure so far to reach a ceasefire that would end the fighting and see the release of hostages.

Reuters contributed to this report