A heated exchange broke out between Israeli Arab and rightist Jewish lawmakers during the Knesset's inaugural session on Wednesday, as members of the two groups wrangled over Israel Defense Forces soldiers' controversial testimonies from the war in Gaza and t-shirts printed by troops following the operation with pictures and captions seen as encouraging violence.

Both issues were exposed over the last few weeks in Haaretz, raising controversy both within and outside the IDF.

During the Knesset session on Wednesday, a spat erupted between Arab MKs and those from the rightist National Union party, during which expressions such as "terrorist", "fifth-column", and "Kahanist" were all used.

The chairman of the Israeli Arab Balad party, MK Jamal Zahalka, said that during a battle in the Gaza Strip town of Beit Lahia, IDF soldiers "killed civilians, and bodies were strewn in the street."

In response, National Union MK Uri Ariel called him a "fifth column," while National Union MK Michael Ben Ari dubbed Hadash Chairman MK Mohammed Barakeh "a terrorist."

Barakeh responded to the allegation by saying: "Shut up, you Kahanist."

"The army is both unable and uninterested in exposing the horrific truths regarding the actions of both the military and the soldiers," Barakeh told the Knesset. "An investigation will indeed take place, but I am not counting on anything coming from an internal military instigation or from any kind of artificial government approved inquiry."

"An investigation will indeed come and those war criminals, who perpetrated crimes against humanity, will meet a full punishment," he warned, without elaborating.

With regard to the soldiers' contetnious shirts, which featured dead Palestinian babies, mothers weeping on their children's grave, a child in the crosshairs of a sniper's rifle and blown-up mosques, Barakeh said: "We were informed that the IDF's chief education officer released a message ordering soldiers to not overstep military sense of humor. What sense of humor is he talking about?"

"He's talking about soldiers, units, it wasn't just individuals who printed shirts showing pregnant women and an English caption saying 'one shot - two dead,'" Barakeh added. "Is that humor? Is that how the chief education officer treats crimes? Treats the atmosphere which enables these crimes?"

Meanwhile, MK Ben Ari claimed that the expose on soldiers' testimonies ? describing lax rules of engagement in Gaza - was a manifestation of "a decaying process happening in Israeli society, and which has followed us for almost 40 years, from the time of Siach Lochamim," referring to a book in which soldiers famously spoke about their feelings at the end of the 1967 Six-Day War.

Ben Ari denounced what he called "an informant mentality which undermines our national stamina." He called out to the new government to "dismantle the [Oranim] pre-military training academy [from where these Gaza soldiers graduated and delivered their testimonies] and to prosecute anyone who damaged Israel's security."

Deputy Defense Minister Matan Vilnai said that the chief military prosecutor decided to close the cases concerning war-crime evidence "since it appeared that none of the testimonies relied on solid evidence."

"None of those who spoke saw things for themselves but relied on second- and third-hand rumors," Vilnai said. "When they spoke about these things in their academy discussion, they didn't think of the ramifications of having no evidence, and spoke as young people often do, saying anything that was on their chest."

Vilnai added that it was "The chief military prosecutor who initiated the case himself, and it was his decision to close it. I have no doubt as to the purity of his intentions."