Israel carried out air strikes in the Gaza Strip for a second day on Saturday. More than 20 people have been killed so far.

Israel launched a military campaign against the Iran-backed Palestinian militant group, Islamic Jihad, on Friday. A senior military official of the group was killed.

On Saturday, strikes hit targets in Gaza City, which Israelis say the militants used as bases.

Footage taken by NHK captured the sound of explosions as well as black smoke and flames rising among crowded buildings. A video also shows rockets and intercepting missiles flying in the night sky.

Gaza's health ministry says at least 24 people, including women and children, have been killed and more than 200 wounded so far.

Islamic Jihad fired rockets into southern Israel. No deaths have been reported on the Israeli side, but several people are said to have been wounded while taking shelter.

UN Special Coordinator for the Middle East Peace Process Tor Wennesland called on all parties to de-escalate the situation.

Wennesland said in a statement that global resources are stretched and international financial support for a renewed humanitarian effort in Gaza will not be easily available.