The Israeli military prevented two more terrorist cells from infiltrating southern Israel via tunnels Monday as fighting raged on between Israel and Hamas.

Israeli Defense Forces said it killed 10 militants in the offensive Monday, according to The New York Times.

Roads were closed and residents were ordered to stay indoors after 10 a.m. Monday before the incident was over.

A statement from the IDF said that "two terror squads were detected" and that an airstrike targeted one group of militants, and soldiers staged a ground offensive to thwart the other group of militants.

Hamas militants also issued a statement Monday, saying they carried out an "operation behind the enemy's front lines and the clashes are still going on."

Thirteen Israeli soldiers were killed in the fighting, which occurred in Shejaiya in eastern Gaza City late Sunday into Monday. The deaths increase the total number of Israel soldiers killed in the fighting to 18. Five IDF soldiers are currently in the hospital in serious or critical condition, 15 are in stable condition and 40 have minor injuries. Sixty Palestinians died in the clashes.

Since Israel's ground invasion of Gaza began, at least 130 Palestinians have been killed, raising the Palestinian death toll to 508. Around 3,130 have also been wounded since the operation began 14 days ago.

The United Nations reported that nearly 100,000 people from Gaza are in 67 shelters, and an airlift of 45,000 mattresses and 10,000 blankets are being flown to Gaza from Dubai.

Thousands of Palestinians evacuated Gaza over the weekend with some leaving in cars and others in donkey carts.

Israel attacked the Abu Jamei family home near the southern town of Khan Younis Monday night, killing 26, which is the highest number of casualties so far in a single strike during the conflict. Witnesses also said that artillery shelling killed 11 people in a residential area.

The IDF increased artillery shelling in central Gaza near the refugee camps of El Mughazi and El Bureij, where the Israeli military warned civilians to evacuate ahead of time.

The IDF airdrops pamphlets warning of an impending attack prior to shellings, in addition to sending small warning rockets to hit the top of roofs in order to warn residents to evacuate the buildings.

While Hamas blames Israel for civilian deaths, Israeli officials said that it is well known that Hamas militants purposely launch rockets from densely populated civilian areas in order to use their people as human shields. Palestinians thereby gain international sympathy for their plight, according to Israeli officials.

In Israel, rocket fire slowed from Gaza, but more than a dozen sirens sounded around midday Monday. One rocket hit a home in Sderot, which is near Gaza, and another landed in an open field located near Tel Aviv.

More than 90 percent of Palestinian rockets are intercepted through Israel's sophisticated Iron Dome antimissile defense system.

Funerals are scheduled for at least five soldiers from the Golani Brigade who were killed Sunday. The IDF also said it is not certain as to whether a soldier has been captured alive, which Hamas claimed Sunday night.

The Israeli military said that one of the soldiers killed, Max Steinberg, 24, was an American who volunteered for the Israeli Army. Steinberg was from Southern California.

The United Nations Security Council held an emergency session late Sunday, saying they have "serious concern" about the high number of civilian Palestinian casualties. The Security Council demanded an end to the bloody conflict.

"It's a very difficult question," a senior Israeli military official said Sunday night, speaking on the condition of anonymity.

"We have a mission, and we are going to fulfill it — Israel is not going to leave the threats of tunnels beneath the border between Gaza Strip and Israel," he said. "After 13 days of fighting, and so many casualties, I believe that it's the right time for all sides to stop."

The incursions into Israel from Hamas is prompting new crackdowns by the IDF, which is trying to focus on shutting down the militants' tunnels. The IDF discovered that Hamas' network of tunnels is more sophisticated than was anticipated. There are many tunnels that have multiple points of entry and exists, which makes them difficult to track down and destroy.

"Our goal now is to finish the job by really destroying as much tunnels as we can, if not all of them," he said. "It's very difficult for me to say all of them because there's always a chance we don't know all the tunnels, and what you don't know you simply don't know."

On Saturday morning, eight men from Gaza disguised in Israeli military uniforms attacked two Israeli army jeeps, killing a reserve officer and a soldier. The militants also entered into southern Israel Saturday with one of the militants carrying handcuffs and tranquilizers, which the Israeli military said indicated that they were planning to abduct an Israeli soldier.

Militants also exited from a tunnel near Kibbutz Nir Am Sunday morning, which is a community of 400 people that was established before the state of Israel. Militants exited about 500 yards from the center of the community.

An Egyptian-backed cease-fire was implemented last week, but it was short-lived, as Hamas violated the cease-fire by lobbing rockets into southern Israel.

President Obama is now sending Secretary of State John Kerry to Cairo to help facilitate an end to the fighting.

Kerry will work with Israelis, Egyptians and officials from the Palestinian Authority to implement a cease-fire agreement.

However, some Israeli officials said they will not stop the offensive until all the tunnels are destroyed.

Tzipi Livni, Israel's justice minister, told The New York Times that the "demilitarization of Gaza" is imperative, but that first they need to focus "on the need to stop these terrorists, to act against these tunnels, and to stop these rockets against Israel."