The capture or death of Lt. Hadar Goldin, the 23-year-old Israeli soldier who Israel believes was dragged into Hamas's underground tunnel network Friday, has the potential to alter the diplomatic landscape over Gaza.

The abduction of an Israeli soldier would provide Hamas with a tactical achievement that could strengthen its bargaining position. But it would have come at a cost: it placed Hamas on the defensive for violating a U.N.-backed cease-fire that offered Gazans their first greatest hope of relief in the 26-day long war. It also relieved political pressure on Israel, which was sharply criticized by the U.N. and the White House following reports that it shelled a U.N. shelter in Gaza on Wednesday, killing more than 16 civilians.

The total fallout over Goldin's disappearance won't be known for days and Hamas has claimed that it is not holding him. In a statement issued on Saturday, Hamas suggested that the Israeli soldier might have been killed alongside his Palestinian captors by a retaliatory Israeli bombardment. 

But if the Palestinians have him, his capture could take the two sides down one of two sharply different paths. Kidnapped soldiers have tremendous emotional resonance in Israel, who a few years ago swapped 1,000 Palestinians for a single missing soldier, Gilad Shalit. Hamas would expect Israel to make far-reaching concessions this time around as well. But with the Israeli public strongly supporting Israeli Prime Minister Benjamin Netanyahu's tough approach to the confrontation, the capture could also lead to Israel intensifying its military campaign in an effort to find and rescue the missing soldier. That could further escalate the already bloody conflict, which has killed more than 1,400 Palestinians, many of whom were civilians, and 60 Israelis, mostly soldiers.

As fighting spread throughout Gaza Friday, U.S., U.N., and other international dignitaries cast blame squarely on Hamas.

"I have unequivocally condemned Hamas and other Palestinian factions that were responsible for killing two Israeli soldiers and abducting a third almost minutes after a cease-fire was announced," President Barack Obama said at a White House news conference. "If they are serious about trying to resolve this situation, that soldier needs to be unconditionally released as soon as possible."

Obama also acknowledged that it would be "be very hard to put a cease-fire together if Hamas can't follow through."

U.N. Secretary General Ban Ki-moon made clear that although his organization had "no independent means to verify" what happened in Gaza, the blame likely rested at Hamas' feet. "The secretary general condemns in the strongest terms the reported violation by Hamas of the mutually-agreed humanitarian cease-fire, which commenced this morning," according to a statement from Ban's office. "He is shocked and profoundly disappointed by these developments."

In the short term, the incident is likely to escalate the violence in Gaza, raising political pressure at home on Israel to exact a human cost against Hamas, possibly through targeted attacks on the group's leaders. Already, Israeli forces have heavily bombarded the area around Rafah, where two Israeli soldiers were killed and Goldin was captured during an operation designed to find and destroy tunnels in the area. Palestinian health officials in Gaza claimed that Israel bombardment killed 35 Palestinians and more than 100 others in the Rafah area. Hamas also carried out rocket attacks against Israel throughout Friday.

Hamas's military wing, the Al-Qassam Brigades, said it doesn't know what became of Goldin. But in a statement issued Friday, Hamas denied breaching the cease-fire, according to a report in the New York Times. The group said it clashed with Israeli forces that advanced into eastern Rafah an hour before the cease-fire went into force.

"Until now, we have no idea about the disappearance of the Israeli soldier," the statement read. "We do not know his whereabouts or the conditions of his disappearance." Hamas said that it had lost touch with its "troops deployed in the ambush" of Goldin's unit. "Our account is that the soldier could have been kidnapped and killed together with our fighters."

Late Thursday, Hamas and Israel agree to observe a U.N.-brokered 72-hour "humanitarian cease-fire" to give Palestinians relief from weeks of relentless violence to bury their dead, tend to their wounded, and stock up on food and water. The agreement — which was announced jointly Thursday night by Ban and Secretary of State John Kerry — was also intended to allow Egyptian-hosted talks between Palestinian and Israeli officials to resume this weekend in Cairo to reach a more "durable cease-fire," according to the joint statement.

Speaking at the White House press conference, Obama said the violation of the cease-fire raised questions about whether Hamas actually has control over Gaza's armed militants and whether it can keep its promises. "It's going to take some time" to repair the diplomatic damage, Obama told reporters.

Since fighting began on July 8, the United States, Israel, Egypt Jordan, and Saudi Arabia have sought to craft a cease-fire plan that would deny Hamas any political rewards for its military campaign against Israel and strengthen the Palestinian Authority, which has little to show Palestinians after several months of fruitless U.S.-brokered negotiations with Israel.

Hamas has fired nearly 3,000 rockets at Israel in the current armed conflict and has mounted a series of cross-border raids on Israel through its vast underground tunnel network. Hamas' leaders say they will keep fighting until several of their demands are met, including opening border-crossing points into Egypt and Israel, and the release of Palestinians prisoners.

Israel is reportedly open to the idea of easing some restrictions on life in Gaza, but only if it is backed by a credible plan to disarm Hamas and other Palestinian militants and to restore control over Gaza to the Palestinian Authority. 

"This complicates things because the stakes have been raised," said Hussein Ibish, a senior fellow at the American Task Force on Palestine said about Golin's disappearance. "One of the primary goals of Israel is to deny Hamas any kind of benefit. The capture of the soldier makes that more difficult because now they have an asset, this human being that Hamas can trade for tangible deliverables, like a prison swap."

Robert Danin, a former State Department official and a senior fellow at the Council on Foreign Relations, said he is not so sure Israel will follow the same course. Danin said that Israeli military leadership had gone into this conflict instructing its troops to take exceptional steps to prevent the capture of Israeli soldier at any cost, even if it came at the risk of gravely injuring an Israeli soldier.

Of course if Golin is dead, such points are moot. 

Israeli officials, he said, recognize that Israel paid too high a price in the Shalit trade, which only increased Hamas' incentive for capturing more Israeli soldiers. They "are not necessarily going to play it the same way," he said. "They don't want to be in that situation."

Over the short term, Danin said that the violence is likely to intensify as Israel seeks to inflict punishment on Hamas. "They are going to pound Hamas," he said.

"They feel they now have the moral high ground once again," he said. "Yesterday, they were being condemned from the White House for hitting a U.N. school and today even the U.N. is quite strongly criticizing the Palestinians and criticizing Hamas. On the diplomatic level, and in the face of world public opinion, they must feel in a stronger position today."

Jack Guez/ AFP/Getty Images