Israeli tank shelling and airstrikes killed 24 Palestinians including seven children in Gaza on Wednesday, health officials said, the latest violence to undermine the nearly four-month-old ceasefire in the enclave.

Among the dead was a medic who rushed to help victims of a strike in the southern city of Khan Younis and was then killed by a second attack on the same location, health officials said.

Other strikes hit Gaza City in the north, where health officials said a 5-month-old boy was killed.

The attacks come three days after Israel reopened Gaza's main border crossing with Egypt, a big step envisaged by the US-backed truce deal.

"While we were sleeping in our house, the tank shelled us and the shells hit our house, our children were martyred – my son was martyred, my brother's son and daughter were martyred... We have nothing to do with anything, we are peaceful people," said Abu Mohamed Habouch, speaking at a funeral for his family.

Tents in Mawasi, a coastal area near Khan Younis crowded with Gazans displaced by the conflict, had been ⁠ripped apart by the strikes. Nearly all of Gaza's population of over 2 million were forced to flee their homes during the war.

The Israeli military said it launched the strikes in response to Palestinian militants opening fire on Israeli troops operating near its armistice line with Hamas. It said an Israeli soldier was severely injured by the militant fire, which it described as a violation of the ceasefire agreement.

A subsequent statement said one of the Israeli strikes had targeted a senior Hamas commander. A commander from Hamas' smaller ally, Islamic Jihad, and his 11-year-old daughter were among those killed in strikes on Wednesday, according to relatives.

The Israeli military later confirmed in a statement that it had killed an Islamic Jihad commander.

Hamas said Israel's actions undermined efforts to stabilise the ceasefire. In a statement, the group called for "immediate international pressure to halt violations." (Reuters)