TEL AVIV, Israel (NewsNation) — The Israeli Defense Forces are fighting at the heart of Gaza City Thursday, as combat engineers are in the process of entering and blowing up Hamas-built tunnels in the Gaza Strip.

So far, Israel has destroyed about 130 underground tunnel entrances since the war began, according to Rear Adm. Daniel Hagari, the chief military spokesman.

Some tunnels have water and oxygen systems, which leads officials to believe Hamas was planning on hiding inside them.

The IDF said it believes the operation is proceeding as planned but is prepared for an extended stay.

“We have not seen any civilians here, only Hamas. We’ve seen them above ground, coming from the underground, we’ve seen them in lots of places,” said IDF Lt. Col. Ido. “We’ve lost some soldiers. We had a few losses. We’re going forward. We’re doing our job really good, quite good, and we are here until it ends.”

Hamas is believed to have a massive underground network throughout Gaza, allowing it to transport weapons, supplies and fighters.

The IDF opened a humanitarian corridor again Thursday to allow Palestinians to move south away from the fighting in Gaza.

Israel has gained momentum, with its ground forces throttling the terrorist group.

About one million people have been displaced; however, since Egypt opened its border crossing, some have been able to leave the territory, including a couple from Michigan.

“All my mind is back home with my kids and my family, said Zakaria Alarayshi, who recently returned from Gaza. “I don’t know in an hour if there’s going to die or if there’s going to be life. That’s what I’m thinking all the time. I need to get them out before we die.”

Officials hope they evacuate more foreign nationals out of Gaza Thursday following Wednesday’s Rafah Border Crossing closure, due to safety concerns. The State Department said so far, they’ve evacuated 400 U.S. citizens.