The Israel Defense Forces announced Sunday the launching of a formal investigation into the killing of a Reuters cameraman in Gaza, after a U.S.-based human rights group accused troops of either firing recklessly or targeting the cameraman.

Fadel Shana was killed while filming an IDF tank in Gaza on Wednesday, a day of heavy fighting. His final footage shows the tank firing a shell in his direction. Palestinian medics say five others were killed in the incident, including four teenagers.

The IDF denied it had deliberately targeted "uninvolved civilians," and slammed such claims as "false and misleading."

"Following the fighting in the Gaza Strip on April 16th, 2008, the IDF is conducting a field investigation to look into the claims regarding the circumstances of the death of a Reuters cameraman," said the IDF in a statement. "The IDF similarly investigates every claim regarding uninvolved civilians hurt in fighting areas."

The statement also said that, "In accordance with IDF policy, the field investigation will be reviewed by the Military Advocate General."

The New York-based group Human Rights Watch investigated the incident and has accused the IDF of either firing recklessly or targeting Shana.

The IDF announced Sunday that it would launching an investigation, which will be reviewed by the Military Advocate General. The military said that it does not deliberately target uninvolved civilians and denied targeting Shana during a clash with Palestinian militants in the Gaza Strip last week.

Two Gaza teenagers who sustained wounds during Wednesday's IDF ground operation died on Sunday, raising the death toll from that incident to six, Palestinian hospital officials said.

The two boys were 16 and 17 years old. They were reportedly hit by a shell fired from an IDF tank that immediately killed Shana and three other civilians in Gaza.

The teens' deaths came a day after the New York-based organization Human Rights Watch called for a probe into Shana's death. "Israel must investigate the death of a Reuters TV cameraman and three others who were killed in an Israeli strike in Gaza," said a statement from the rights group.

On Saturday, reporters in Gaza City attended a wake for Shana, the 23-year-old cameraman for the Reuters news agency. Shana was the first Gaza journalist to be killed in the territory in the past eight years of Israeli-Palestinian fighting.

The Israeli human rights group B'Tselem said earlier this week it has collected evidence that Shana was killed by a so-called flechette tank shell that spewed tiny darts over a wide radius.

Reuters has released Shana's final video which showed a tank on a distant hilltop open fire. About a second later, the picture turns black. Shana was wearing a bulletproof jacket marked with Press at the time and his vehicle was also marked with TV signs.

"Israeli soldiers did not make sure they were aiming at a military target before firing," said Joe Stork from Human Rights Watch. "There is evidence suggesting they actually targeted the journalists."

The IDF has said it is looking into Shana's death, but will continue to use flechette shells. Rights groups say the weapon is inappropriate for densely populated areas like the Gaza Strip.

Shana was the first Gaza cameraman to die in the conflict. In response, many of his colleagues have posted Shana's picture on their facebook profiles and taped his photograph to their cars.

Eight other journalists were killed covering the West Bank and Gaza Strip since 1992, according to the New York-based Committee to Protect Journalists.

On Saturday, reporters in Gaza plastered their cars with pictures of Shana holding his camera and drove through Gaza City in a convoy, despite fuel shortages have paralyzed most movement in the territory.