A Palestinian man looks out towards destroyed buildings following an Israeli air strike in Gaza City. Photo: Amir Farshad Ebrahimi (flickr)

A stated aim of Israel's military strikes in Gaza was to destroy underground tunnels between Egypt and Gaza because they're used by Hamas to smuggle in weapons.

But Gazans argue that there are two kinds of tunnels running from Gaza to Egypt: militant and civilian. Hamas-controlled tunnels are "supposedly steel-ribbed and large enough for a car to pass through," according to Time. And unlike civilians, who dig in plain sight of the Egyptian border security and Israeli surveillance aircraft, Hamas members are more secretive and obscure about the location of their tunnels.

Gaza's civilians claim their tunnels are necessary. Israel essentially sealed Gaza's borders to everything but humanitarian aid after Hamas took control of Gaza in June 2007, making the tunnels the only means for transporting everything from medicine, cement, chocolate bars, and even lion cubs for the zoo, according to Time.

"It's a lie to say that we use these tunnels to only bring in weapons. We're bringing in the ordinary stuff that keeps Gaza alive. If the Israelis opened the border crossings, we wouldn't have to be doing this," a Gazan resident tells Time.

According to the New York Times, the tunnels are also a primary source of income for some 25,000 young men. Tunnel diggers can earn $100 for every meter they dig — making the tunnels one of the biggest sources of employment in the territory. And they were back to digging as soon as the truce was signed.

"If Israel keeps the borders sealed off, we'll keep digging and only Allah can stop us. Let the Israelis drop their bombs. Without the tunnels we can't survive anyway," says Aymad, a tunnel digger. "And if a bomb catches me underground, well, they won't have to dig my grave."

Given the frequently gloomy headlines regarding the Israeli-Palestinian peace process, many may not be surprised to hear of the latest violence in the region. But NPR reports the current conflict is the heaviest fighting the Gaza Strip has seen since the 1967 Six Day War — and some of the hardest hit seem to be Palestinian civilians.

Following the start of an Israeli ground invasion, the latest reports from the Washington Post indicate that 550 Palestinians have been killed and 2,500 injured — and according to Palestinian health officials, between 24 and 30 percent of those are women and children. Currently the Israeli government has closed Gaza's borders to everything except a small trickle of humanitarian aid, insufficient to meet the needs on the ground.

Mercy Corps is calling for immediate humanitarian access to Gaza to deliver food and other essential supplies. You can sign the petition by clicking here. This petition urges the U.S. government to push for aid to be allowed in now.

You can also help get critical humanitarian items needed once the border is open by donating to Mercy Corps' Gaza Crisis Fund. Mercy Corps has a four-ton shipment of food that's scheduled to enter Gaza tomorrow, and they're deploying additional aid workers to Jerusalem and Egypt to prepare to do more. Check out how Gazan youth involved with Mercy Corps are handling the crisis and keep up-to-date on Mercy Corps' response to the crisis.