The Israeli army ordered a mass evacuation of Palestinians from much of Khan Younis on Monday, a sign that troops are likely to launch a new ground assault in the Gaza Strip’s second largest city.

The order suggested Khan Younis will be the target in the latest of Israel’s repeated raids into parts of Gaza it had previously invaded during the past mearly nine months, pursuing Hamas militants as they regroup, reports AP.

Much of Khan Younis was already destroyed in a long assault earlier this year, but large numbers of Palestinians have since moved back in to escape another Israeli offensive in Gaza’s southern-most city, Rafah.

The order came as Israel released the director of Gaza’s main hospital after holding him for seven months without charge or trial over allegations the facility had been used as a Hamas command center. He said he and other detainees were held under harsh conditions and tortured.

The decision to release Mohammed Abu Selmia raised questions over Israel’s claims surrounding Shifa Hospital, which Israeli forces have raided twice since the start of the nearly nine-month war with Hamas. Abu Selmia and other Palestinian health officials have denied the accusations.

His release triggered an uproar across Israel’s political spectrum. Government ministers and opposition leaders expressed outrage and insisted Abu Salmia played a role in Hamas’ alleged use of the hospital — though Israeli security services rarely unilaterally free prisoners if they have a suspicion of militant links. Prime Minister Benjamin Netanyhu’s office called the release “a grave mistake.”

Monday’s evacuation call covered the entire eastern half of Khan Younis and a large swath of the Gaza Strip’s southeast corner. Earlier in the day, the army said a barrage of rockets out of Gaza was fired from Khan Younis.

The order suggested a new assault into the city was imminent. Israeli forces fought for weeks in Khan Younis earlier this year and withdrew, claiming to have destroyed Hamas battalions in the city. But in other places where the military made similar claims, renewed raids have underscored Hamas’ continued capabilities. Last week, the military ordered an evacuation from the north Gaza district of Shijaiya, where there has been fighting since.