Up to 100 Israeli hostages, including women and children, may have been taken into Gaza by Hamas, hugely complicating any Israeli military operation to free them, the media reported.

Amid shocking images of terrified Israeli soldiers and civilians – some bloodied, others hooded and with their hands tied – being marched away by Hamas militants, the whereabouts and fate of the captives has become one of the most pressing issues for military planners, The Guardian reported.

While spokesperson for the Israel Defense Forces (IDF) Lt Col Jonathan Conricus has said only that a "significant number" of Israeli civilians and soldiers are being held hostage, that number is believed to be in the dozens, with some Israeli news outlets speculating that up to 100 have been taken hostage.

According to reports, while most hostages were taken by Palestinian armed factions, some Palestinian civilians who also entered Israel may have taken captives too.

Among those reported as missing is Jake Marlowe – a British citizen who was attending a music festival in the south of Israel.

His family have been unable to reach him since Hamas infiltrators attacked the event, The Guardian reported.

Conricus said some hostages were alive while others were presumed dead, in line with the practice of Gaza’s militant factions of taking human remains to exchange for Palestinian prisoners in Israeli jails.

"These are numbers that were up until now unimaginable," said Conricus. "This will shape the future of this war."

Israeli TV news aired a stream of accounts from the relatives of captive or missing Israelis, who begged for assistance amid a fog of uncertainty surrounding the fate of their loved ones.

Videos circulating online appear to show Israelis in the hands of Hamas fighters both during their seizure from communities in southern Israel and later in locations in Gaza, with one geolocated video showing a truck being driven through crowds on the Gaza Strip with Israeli hostages, The Guardian reported.

Another video circulating appeared to show an Israeli child in the coastal strip, while yet another appeared to show a wounded Israeli soldier in Gaza being beaten by bystanders.

Despite the displaying of the hostages on their arrival in Gaza, the working assumption is that they will have been quickly dispersed amid fears they will be used as human shields in the likelihood of an Israeli ground assault.

An Egyptian official said Israel had already sought help from Cairo to ensure the safety of the hostages, and that Egypt’s intelligence chief had contacted Hamas and the smaller but more radical Islamic Jihad group, which also took part in the incursion, to seek information, The Guardian reported.