DEIR AL-BALAH, Gaza Strip, July 10 — The Israeli military urged all Palestinians to leave Gaza City and head south Wednesday, pressing ahead with a fresh offensive across the north, south and center of the embattled territory that has killed dozens of people over the past 48 hours.

The stepped-up military activity came as U.S., Egyptian and Qatari mediators met with Israeli officials in the Qatari capital, Doha, for talks seeking a long-elusive cease-fire deal with Gaza’s Hamas militant group in exchange for the release of dozens of Israeli hostages it is holding.  Israel says it is pursuing Hamas fighters that are regrouping in various parts of Gaza nine months into the war. But heavy strikes in recent days along the length of the territory also could be aimed at putting more pressure on Hamas in the cease-fire talks.  In a visit Wednesday to central Gaza, Israel’s military chief, Lt. Gen. Herzi Halevi, said forces were operating in different ways, in multiple parts of the territory “to carry out a very important mission: pressure. We will continue operating to bring home the hostages.”

Israeli airstrikes early Wednesday killed 20 Palestinians in central Gaza, including six children and three women, some of them inside a purported “safe zone” declared by the Israeli military, hospital authorities said.

This second straight night of deadly strikes in the central town of Deir al-Balah and nearby refugee camps came as US , Egyptian and Qatari mediators as well as Israeli officials came together in the Qatari capital, Doha, for talks trying to push through a long-elusive deal for a cease-fire and hostage release. Israel and Hamas had appeared to narrow the gaps in recent days, but obstacles remain.

Strikes early Wednesday hit three houses in the Nuseirat refugee camp, killing 12 people including five children, said authorities at al-Aqsa Martyrs Hospital, where the casualties were taken. An Associated Press reporter counted the bodies.