As fighting between Israel and Hamas militants entered its seventh day on Sunday, Sen. Bernie Sanders, I-Vt., called for a "hard look" at the billions in military aid the U.S. gives to Israel each year. 

"The devastation in Gaza is unconscionable. We must urge an immediate ceasefire. The killing of Palestinians and Israelis must end," the self-proclaimed democratic socialist tweeted Sunday. "We must also take a hard look at nearly $4 billion a year in military aid to Israel. It is illegal to support human rights violations." 

An Israeli firefighter works at the site where a rocket fired from the Gaza Strip, hit the central Israeli town of Holon, near Tel Aviv, Tuesday, May 11, 2021.  A confrontation between Israel and Hamas sparked by weeks of tensions in contested Jerusalem escalated Tuesday as Israel unleashed new airstrikes on Gaza while militants barraged Israel with hundreds of rockets. (AP Photo/Heidi Levine)

The U.S. military aid to Israel includes funding for its Iron Dome defense system, which intercepts short-range rockets and artillery shells.

Sanders, who twice ran for president as the Democratic candidate, has long been a critic of Israel. On the 2020 campaign trail, Sanders proposed leveraging military aid to Israel to push for a change in its policies toward Gaza. 

People insect the rubble of the Yazegi residential building that was destroyed by an Israeli airstrike, in Gaza City, Sunday, May 16, 2021.  (AP)

"My solution is to say to Israel: ‘You get $3.8 billion every year. If you want military aid, you’re going to have to fundamentally change your relationship to the people of Gaza,’" Sanders said in October 2019. "In fact, I think it is fair to say that some of that should go right now into humanitarian aid." 

HOW IS IRAN INFLUENCING THE CONFLICT BETWEEN ISRAEL AND HAMAS? 

The latest outbreak of violence began in east Jerusalem last month, when Palestinians clashed with police in response to Israeli police tactics during Ramadan and the threatened eviction of dozens of Palestinian families by Jewish settlers. A focus of the clashes was the Al-Aqsa Mosque, a frequent flashpoint located on a hilltop compound revered by both Muslims and Jews. 

Hamas began firing rockets toward Jerusalem on Monday, triggering the Israeli assault on Gaza.  

CLICK HERE TO GET THE FOX NEWS APP

More than 100 Palestinians have been killed in the hundreds of airstrikes in Gaza, including 55 children and 33 women, with 1,230 people wounded. Eight people in Israel have been killed in some of the 3,100 rocket attacks launched from Gaza, including a 5-year-old boy and a soldier.

The Associated Press contributed to this report