At least six children were among 21 people killed Wednesday in renewed Israeli attacks on Gaza, the territory's civil defense agency said.

Also 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 partially reopened Gaza's main border crossing with Egypt, a major step in the U.S.-backed ‍truce.

"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 over 2 million population has been forced to flee their homes.