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Tens of thousands of mourners converged in central Israel Tuesday for a funeral service for three kidnapped teenagers whose bodies were found a day earlier in the West Bank.

The three young men were buried side by side in the central Israeli town of Modiin. Mourners arrived in large convoys of buses arranged for the ceremony.

The bodies of the youths -- including one with U.S. citizenship -- were found Monday just north of Hebron in a shallow grave in an open field in the village of Halhul, and led to outpourings of grief and rage in the Jewish State.

Eyal Yifrah, 19, Gilad Shaar, 16, and Naftali Fraenkel, a 16-year-old with dual Israeli-American citizenship, disappeared on June 12 while hitchhiking home.

Israeli Prime Minister Benjamin Netanyahu and President Shimon Peres eulogized the teens at the joint funeral Tuesday, located near the boys’ family homes, according to the Jerusalem Post.

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    "Today has spontaneously become a national day of mourning,” Netanyahu said.

    The bodies were wrapped in blue and white Israeli flags and laid on stretchers.

    Prior to the funeral, hundreds of people participated in separate memorial services Tuesday at the teens’ respective homes in Elad, Talmon, and Nof Ayalon, the Jerusalem Post reported.

    Defense Minister Moshe Yaalon, speaking at the ceremony for Yifrah in Elad, said the boys were “murdered just because they were Jewish."

    "Recently, the people of Israel went through a great trauma," said Shirel Shaar, Gilad's younger sister, speaking at his ceremony in Talmon. "We are living as if we are in a movie, whose ending is as bad as can be," she said. "I don't have a brother anymore."

    Finance Minister Yair Lapid added, “We are burying a child today, a child who could have been the child of any one of us."

    Netanyahu convened his security Cabinet for an emergency meeting Tuesday to discuss a response to the killings.

    Ahead of the late-night meeting, Netanyahu vowed a tough response against Hamas, saying Israel "will not rest" until it catches the killers. He also warned of stepped up military activity in Hamas-controlled Gaza if rocket fire out of the territory continues.

    "Hamas continues to support, even at this time, the kidnappings of our citizens and is directly responsible for firing rockets and mortars at our territory, including in recent hours," Netanyahu said in a statement aired on national TV. "If there is a need, we will broaden the campaign as much as needed."

    Netanyahu’s comments came after Israel's air force launched strikes on dozens of targets in the Hamas-controlled Gaza Strip.

    The Israeli Air Force conducted airstrikes early Tuesday morning against 34 targets in the Hamas-controlled Gaza Strip in response to rocket attacks against Israel's southern communities. It was not immediately clear if the airstrikes, which targeted Hamas and Islamic Jihad assets in the strip and came after more than 20 rockets were fired into southern Israel over the past two days, resulted in any casualties, the Jerusalem Post reported.

    Also on Tuesday, a Palestinian who Israel said was a member of Hamas was shot dead when he threw a grenade at forces carrying out an arrest raid in the West Bank. The man was the first casualty since the bodies were found in a shallow grave in an open field in the village of Halhul.

    Israel has said two well-known Hamas operatives from Hebron are the primary suspects in the teens’ deaths. The men, Amer Abu Aisheh, 33, a locksmith, and Marwan Qawasmeh, 29, a barber, have not been seen since the teens disappeared, and military officials said the search for them would continue.

    Israeli soldiers blew up a door of Abu Aisheh's home in Hebron early Tuesday, causing damage to the home, but did not destroy the rest of the house, said an Israeli military official, speaking on condition of anonymity due to protocol. He did not elaborate. Flames were seen after the blast.

    "[The teens] were kidnapped and murdered in cold blood by animals," Haaretz quoted Netanyahu as saying at a hastily arranged security cabinet meeting on Monday. "In the name of the whole of Israel, I ask to tell the dear families -- to the mothers, the fathers, the grandmothers and the grandfathers, the brothers and sisters -- our hearts are bleeding, the whole nation is crying with them."

    A Defense official said, based on the investigation, that the teens were shot soon after they were abducted. He spoke anonymously in line with protocol as the investigation is still ongoing.

    President Obama called the killings of the teens a "senseless act of terror."

    "As a father, I cannot imagine the indescribable pain that the parents of these teenage boys are experiencing," he said in a statement. "The United States condemns in the strongest possible terms this senseless act of terror against innocent youth."

    Fraenkel's cousin, David Halberstam, told Fox News that the family is devastated, saying his 90-year-old mother, who lost relatives in the Holocaust, "broke down" when she heard the news.

    "It's -- your worst fears are realized. And it's awfully, awfully difficult. We haven't quite absorbed everything yet," he said.

    The abductions outraged the Jewish state as well as the international community, and several vigils and rallies were held around the U.S. during the intensive hunt. Hundreds of Palestinians took part in the search, dubbed "Brother's Keeper."

    Large gatherings were also held in Tel Aviv's central Rabin Square, and at the West Bank junction where the youths were abducted, with Israelis singing hymns and songs, praying and lighting candles shaped in the names of the youths or the Jewish Star of David.

    The three youths disappeared as they were heading home from a West Bank religious school. Israeli officials said at the time that one of the teens called a police emergency line around 10:25 p.m. local time and said: "We've been kidnapped." They were not heard from again.

    Palestinian Authority President Mahmoud Abbas criticized the kidnapping and pledged help in the search but denied there was evidence linking Hamas to the crime. Hamas, which governs the Palestinian territories jointly with the PA, praised the kidnapping without claiming responsibility.

    Hamas spokesman Sami Abu Zuhri accused Israel of using the murders as a pretext for aggression.

    "Only the Israeli version of the events has been published. Israel is attempting to make way for aggression against us, against the Hamas," Zuhri said. "We reject all Israeli allegations and threats against us. We are already used to it and will know how to defend ourselves. No Palestinian group, Hamas or any other group, has taken responsibility for the action, and thus the Israeli version can't be trusted."

    Israeli forces searched more than 1,000 sites for the missing teenagers, rounding up Hamas and Islamic Jihad suspects as part of the operation.

    Binyamin Proper, who was among the civilian volunteers who found the bodies, told Channel 2 TV that a member of the search party "saw something suspicious on the ground, plants that looked out of place, moved them and moved some rocks and then found the bodies. We realized it was them and we called the army."

    The Associated Press contributed to this report.