After two weeks of fighting in the Gaza Strip, Israeli military forces have killed over 500 Palestinians with airstrikes and artillery, while tens of thousands of Palestinians have been displaced, reports the Los Angeles Times.

To help Palestinian refugees who have been forced to flee from their homes, U.S. Secretary of State John Kerry announced that the U.S. will send $47 million in humanitarian aid. The Associated Press reports that $15 million of the aid will be directed towards the United Nations' refugee mission in Gaza.

"We are deeply concerned about the consequences of Israel's appropriate and legitimate effort to defend itself," Kerry said while in Cairo on Monday.

"No country can stand by while rockets are attacking it, and tunnels are dug in order to come into your country and assault your people," Kerry added, according to the Times of India.

Last week, the violence in the Gaza Strip between Israel and Hamas intensified after Israeli Prime Minister Benjamin Netanyahu ordered a military ground invasion.

According to a military statement, the goal of the ground operation is to "establish a reality in which Israeli residents can live in safety and security without continuous indiscriminate terror," reports the New York Times.

Witnesses in Gaza reported heavy artillery and helicopter fire in addition to naval shelling along the Gaza border as ground troops moved in the north. Israel also moved armed naval boats by Gaza's port.

"The prime minister and defense minister have instructed the IDF (Israel Defence Force) to begin a ground operation tonight in order to hit the terror tunnels from Gaza into Israel," the statement said, according to Reuters.

The Israeli military released a statement that said the operation will include "infantry, armored corps, engineer corps, artillery and intelligence combined with aerial and naval support."

The ground invasion began just a day after Israel launched an intense attack on the Gaza strip, targeting the homes of high-ranking Hamas leaders.