A Palestinian paramedic who has been missing since an Israeli attack that killed 15 other emergency workers in southern Gaza three weeks ago is being detained by Israeli authorities, the International Committee of the Red Cross has said.

The ICRC confirmed in a statement that it had “received information” that Palestine Red Crescent Society (PRCS) medic Assad al-Nassasra was being held “in an Israeli place of detention”.

The PRCS said Mr Nassasra was “forcibly abducted” by Israeli troops following the attack and called for his immediate release.

The Israel Defense Forces (IDF) has not confirmed his detention. A spokesperson said it was aware of the claim about his whereabouts.

The bodies of eight PRCS medics, six Civil Defence first responders and a UN staff member were found buried in shallow graves on the outskirts of Rafah, a week after their convoy came under fire from Israeli troops there on 23 March.

One other PRCS medic survived and said he was released by Israeli forces after being detained for around 15 hours.

The PRCS has said the incident was a “full-fledged war crime”, accusing Israeli forces of “a series of deliberate attacks” on its staff and their ambulances as they answered a call to help casualties.

It has called for an independent international investigation into the incident and for those responsible to be held to account.

Last Monday, the IDF said a preliminary inquiry indicated troops “opened fire due to a perceived threat following a previous encounter in the area, and that six of the individuals killed in the incident were identified as Hamas terrorists”, without giving evidence.

The Palestinian Red Crescent rejected the allegation, as did the other surviving paramedic.

The IDF initially said its troops fired on “suspicious vehicles” driving in darkness with their headlights and emergency lights off.

But it later said that account was “mistaken” after a video found on the mobile phone of medic Rifaat Radwan, who was in the same ambulance as Assad al-Nassasra, showed the convoy was using its emergency lights.

At the end of the video, the ambulances are seen pulled over on the roadside. The sound of gunfire can be then heard just as Radwan gets out of his ambulance. It continues for more than five minutes and Radwan is heard saying his last prayers, before the voices of Israeli soldiers are heard approaching.

Audio analysis by BBC Verify of the footage found Israeli troops fired more than 100 times during the attack, with some shots taken from as close as 12m (39ft) away.

In a statement released on Sunday, the PRCS said: “We have been informed by the International Committee of the Red Cross that PRCS medic Assad al-Nassasra is being held by the Israeli occupation authorities.

“His fate had remained unknown since he was targeted along with other PRCS medics in Rafah.”

It added: “We call on the international community to pressure the occupation authorities to immediately release our colleague, medic Assad, who was forcibly abducted while carrying out his humanitarian duties.”

A spokeswoman for the PRCS told the New York Times Mr Nassasra had worked for the PRCS for 16 years, and was married with six children.

An ICRC spokeswoman said it had informed Mr Nassasra’s family and the PRCS after receiving information about his whereabouts.

It noted: “The ICRC has not been granted access to visit Assad al-Nassasra. The ICRC has not been able to visit any Palestinian detainees held in Israeli places of detention since 7 October 2023.”

The Israeli military launched a campaign to destroy Hamas in response to an unprecedented cross-border attack on 7 October 2023, in which about 1,200 people were killed and 251 were taken hostage.

More than 50,940 people have been killed in Gaza since then, according to the territory’s Hamas-run health ministry.