The first pause in hostilities between Israel and Hamas in nearly seven weeks came into effect on Friday morning.

The four-day cease-fire started slightly later than the planned 7 a.m. local time, as the Israeli military carried out last-minute airstrikes on the war-torn Gaza Strip.

The Israel Defense Forces released a statement announcing the completion of "its operational preparations according to the combat lines of pause." Amid the early morning hours in the area of Gaza's largest hospital, Al-Shifa, Israeli troops destroyed a "route of underground tunnels and a number of tunnel shafts" that the IDF alleged was used by Hamas, which rules the enclave.

"The war is not over yet," the IDF added. "The suspension of fires for humanitarian purposes is temporary. The northern Gaza Strip area is a dangerous war zone and it is forbidden to move around."

"For your safety, you must remain in the humanitarian zone in the south of the Strip," the IDF continued. "It is only possible to move from the north of the Strip to its south via Salah al-Din Road. The movement of residents from the south of the Strip to the north will not be allowed in any way."

The release of some hostages being held by Hamas and other Palestinian militant groups in Gaza, in exchange for the release of some Palestinian prisoners in Israel, is expected to begin at 4 p.m. local time.

-ABC News' Bruno Nota, Joe Simonetti and Morgan Winsor

ABC News has learned more details about how the tentative release of Israeli hostages will play out from an Israeli source with direct knowledge of the current plan.

The Red Cross will pick up the hostages and transfer them through Egypt to Israel, the source said.

Once on the Israeli side a specially trained group of soldiers will identify them and cross-reference them from a list, according to the source.

Then the hostages will be offered a chance to speak to loved ones by phone, and then the adult hostages will be debriefed by the Shin Bet, the source said.

Women and girls released will be offered a rape kit, according to the source.

The hostages will be reunited with their families and be transported to several hospitals, the source said.

-ABC News' Matt Gutman

Israel Defense Forces spokesperson Daniel Hagari provided an update Thursday evening as families await the negotiated return of some of the hostages from Hamas.

He said they received the list of women and children who will be part of the first group released and the IDF has informed their families.

"This is a hard and tense evening for us all," Hagari said.

He reiterated that the current negotiation with Hamas is "not the end of the process of returning the hostages, but the beginning of it."

"Our hearts are with the families, and we will continue to accompany them, to keep them updated with the reliable information that we have," he said.

-ABC News' Dana Savir

All areas of the Gaza Strip will receive medical supplies and fuel and cooking gas during the cease-fire, according to Hamas.

In a statement, Hamas said Israeli planes will stop flying over the southern Gaza Strip entirely during the cease-fire. Planes will stop flying over the northern Gaza Strip for six hours a day during the cease-fire.

Israel confirmed that it has received a list of hostages who will be released and officials are in contact with the hostages' families.

President Joe Biden said Friday that the release of 24 hostages held by Hamas in Gaza is "just the beginning" of a plan to free 50 of the more than 230 captives over four days.

“It's only a start, but so far it's gone well,” Biden said in a televised address from Nantucket, Massachusetts, where he and first lady Jill Biden are vacationing.

He said Friday's hostage release is part of a deal "reached by extensive U.S. diplomacy, including numerous calls I've made from the Oval Office to leaders across the region," including calls with Israeli Prime Minister Benjamin Netanyahu, Egyptian President Abdel Fattah El-Sisi and the emir of Qatar.

“All of these hostages have been through a terrible ordeal, and this is the beginning of a long journey of healing for them,” Biden said. “Today has been a product of a lot of hard work and weeks of personal engagement.”

Biden said that under the deal, more hostages would be released over the next three days with 50 being "our goal." But he added, "We also will not stop until we get these hostages brought home and an answer to their whereabouts.”

The president said U.S. officials do not know when Americans -- including two women and 4-year-old Abigail Edan, whose parents were killed by Hamas terrorists -- will be among those that are released or their conditions. He added, “We expect it to occur” and that it’s his “hope and expectation” that it “will be soon.”

Biden said the four-day cease-fire that was negotiated for the release of the hostages will allow time to "accelerate and expand humanitarian assistance going into Gaza."

Speaking of the children freed on Friday, one just 2 years old, Biden said, “The teddy bears waiting to greet those children at the hospital are a stark reminder of the trauma these children have been through at such a very young age.”

-ABC News' Justin Gomez