JERUSALEM (AP) — Israel said it launched an airstrike on a Hamas militant in southern Gaza late Wednesday in retaliation for an attack earlier in the day that wounded five Israeli soldiers.

The strike was the latest test for a fragile ceasefire that has mostly held up since early October, despite claims of violations by both Israel and Hamas. Hamas put out a statement condemning the Israeli strike in Khan Younis.

Earlier Wednesday, Israel received remains of what could be one of the last hostages in Gaza and said it would begin allowing Palestinians to leave the war-torn territory through a border crossing with Egypt.

Prime Minister Benjamin Netanyahu said Hamas violated the ceasefire Wednesday when, according to the army, militants emerged from an underground tunnel and attacked Israeli soldiers in an area under their control.

Israel has accused Hamas of ceasefire violations before launching previous waves of airstrikes. Strikes killed 104 people in late October and 33 people in late November, according to local health officials.

The remains found Wednesday by militants in northern Gaza were returned to Israel, where they were being examined by forensics experts. Remains militants handed over on Tuesday did not match either of the last two hostages in Gaza.

The return of all the hostages taken on the Oct. 7, 2023, attack that started the war is a key element of the first phase of the ceasefire that began in October. In exchange, Israel has been releasing Palestinian prisoners.

Once the last hostages’ remains are returned and Israel releases more Palestinian prisoners in exchange, the U.S.-backed ceasefire plan is supposed to advance to the next phases, which call for creating an international stabilization force, forming a technocratic Palestinian government and disarming Hamas.

Earlier on Wednesday, Netanyahu said forensic testing showed that partial remains returned by militants on Tuesday did not match either of the hostages still in Gaza. Palestinian militants later said they had found more remains in northern Gaza and turned them over to the Red Cross, which is acting as an intermediary.

The two remaining bodies of hostages taken into Gaza are Israeli Ran Gvili and Thai national Sudthisak Rinthalak. Gvili was an Israeli police officer who helped people escape from the Nova music festival during the Oct. 7 attack and was killed fighting at another location. Sudthisak Rinthalak was an agricultural worker from Thailand who had been employed at Kibbutz Be’eri, one of the hardest-hit communities in the attack.

A total of 31 workers from Thailand were abducted, the largest group of foreigners to be held in captivity. Most of them were released in the first and second ceasefires. The Thai Foreign Ministry has said in addition to the hostages, 46 Thais have been killed during the war.

Under the terms of the ceasefire, the long-closed Rafah crossing is to be opened for medical evacuations and travel to and from Gaza. The World Health Organization says there are more than 16,500 sick and wounded people who need to leave Gaza for medical care.

It was not immediately clear when the border crossing would be opened, however.