Israel's military says it has hit more than 400 targets in the Gaza Strip in one day after resuming its offensive against Hamas. Health authorities in Gaza say more than 200 people have died and 589 others have been wounded.

The Israeli military resumed its operations against Hamas on Friday morning after a pause in fighting had expired.

It said in a social media post on Saturday morning that it struck some 400 targets. The military said they included a Hamas stronghold in the northern city of Beit Lahia, which it attacked from the air and on the ground with tanks.

Israel also said it conducted air strikes on more than 50 targets in the southern city of Khan Yunis.

An Arabic-speaking spokesperson for the Israeli military urged people to evacuate if they are in zones designated for evacuation as shown on a map of Gaza released on social media.

Footage taken in Gaza on Saturday morning shows rising pillars of black smoke.

Qatar-based satellite TV new service Al Jazeera said there were fierce air strikes in Gaza from Friday night through Saturday morning.

Many people fled northern Gaza for the southern part of the enclave after Israel launched an offensive in October.

There is growing concern about the possibility of more casualties in southern Gaza if Israeli forces continue their attacks in the region.

Hamas's armed wing, the Al-Qassam Brigades, said on social media that it fired rockets toward the Israeli town of Sderot and Israel's largest business hub of Tel Aviv in retaliation for Israeli attacks on civilians.

The Palestine Red Crescent Society said in a social media post on Friday that Israeli forces were preventing the entry of aid through the Rafah border crossing. It said Israeli forces informed all organizations and entities operating there that the entry of aid trucks from Egypt to Gaza is prohibited from Friday until further notice.

There is growing concern that a delay in the transport of aid supplies into Gaza could cause the humanitarian situation there to further deteriorate.