(NewsNation) — More than 200 people remain in captivity following the Oct. 7 Hamas assault on Israel, complicating the reality for Israeli ground forces that are expanding operations in northern Gaza.

Gershon Baskin, Israel’s former top hostage negotiator, says the Israeli government has a “moral responsibility” to exhaust every avenue possible to negotiate the release of the hostages before troops go scouring through underground tunnels in Gaza looking for them.

“On the one hand, (the invasion is) for sure putting more pressure on Hamas; on the other hand, it provided intelligence information to help at least rescue one hostage,” Baskin said Tuesday on “Elizabeth Vargas Reports.” “I think that it’s pretty easy to assume that once the full-scale invasion begins, the pathway toward a negotiated release of the hostages probably ends.”

Hamas militants abducted about 240 people during the incursion into Israel, some of them Americans. Israeli troops successfully rescued one of the captives Monday, and Tuesday, a Hamas spokesman said they plan to release some non-Israeli hostages in coming days.

Hamas has previously released four hostages, and has said it would let the others go in return for thousands of Palestinian prisoners held by Israel, which has dismissed the offer.

Hamas released a video Monday of three of the hostages, who called on Israeli Prime Minister Benjamin Netanyahu to engage in the prisoner swap. A family member of one of the women in the hostage video said it provided hope that she will return home.

“I think what we really need to focus on is that there still remains an opportunity to bring out the hostages alive as a negotiated agreement between Israel and Hamas,” Baskin said. “I believe the Israeli government has a moral responsibility to exhaust every possibility to bring out the hostages before there’s a need for the entire Israeli army to go searching for them in the tunnels underneath the ground.”

Hamas has built an extensive network of tunnels underneath the Gaza Strip over the years, and it’s believed to be a likely location the hostages are being held. The Israel Defense Forces says aerial bombardments over the past three weeks have destroyed some of those tunnels, which Hamas uses to store weapons, ammunition and other supplies.

Israel says it targeted one such tunnel in a series of airstrikes Tuesday on the densely populated Jabaliya refugee camp. The Israeli military said dozens of militants were killed, including a key Hamas commander for northern Gaza.

All the while, families continue to plead with government officials to get back their relatives. It’s unclear if a deal is near.

“For the last three days, there’s been radio silence basically from all parties, which for me is a sign that the negotiations are (at a) very sensitive point and very intensively going on, both in Qatar and in Egypt,” Baskin said. “We know that the head of the (Israeli spy agency) Mossad flew to Qatar, we know that the previous head of Mossad also flew to Qatar, and that’s an indication of how serious the negotiations are.”

The Associated Press contributed to this report.