It looked like a significant gain for Hamas when a senior official claimed that fighters had captured an Israeli officer near the Gaza Strip town of Rafah, in an operation apparently designed to take advantage of a 72-hour ceasefire and improve the terms of any eventual cessation of hostilities.
Israel confirmed quickly that 2nd Lt Hadar Goldin was missing and that it feared he had been abucted, though Hamas later denied it was holding him. Uncertainty about the details and timing of the incident nothwithstanding, concern for the officer's fate looks certain to reinforce the Israeli government's determination to carry on fighting.
Any capture of Israeli personnel inevitably recalls the case of Gilad Shalit, a young conscript who was seized by Palestinian fighters on the border with Gaza in 2006 and held for five years before being traded for the release of 1,027 Palestinians.
Gershon Baskin, an Israeli peace activist who helped to negotiate Shalit's release, said on the basis of the initial claim he believed that the Izzedine al-Qassam brigades, the military wing of Hamas, had made a grievous error. "Al-Qassam just signed the death sentence of many Hamas leaders," he tweeted. "There will not be another Shalit deal."
Capturing Israelis, dead or alive, is seen by Hamas and other Palestinian groups as a strategic weapon that can help to redress the huge military imbalance between the two sides. Corpses and body parts have been traded in previous exchanges.
Ominously, one senior Israeli figure compared the Rafah capture to the "strategic" cross-border operation mounted by Hezbollah in 2006, in which three Israelis soldiers were killed and two captured in an elaborate ambush – and which triggered that year's war. Two years later, the bodies of the two soldiers were returned to Israel by Hezbollah in exchange for a Palestinian and four Hezbollah prisoners.
"This prevents any possibility of dialogue," Giora Eiland, a former general and national security adviser, told Israel Radio. "No Israeli government would agree to that after a breach like this of an agreed ceasefire." Israel would now be unlikely to agree to any truce without at least obtaining information via the Red Cross about the prisoner, he said.
If confirmed, the Hamas move would suggest that the al-Qassam brigades had not been prepared for negotiations without a significant victory – and a strong negotiating hand – to show for the sacrifices of the last three weeks, in which more than 1,400 Palestinians have now been killed.
Shalit's capture is the most recent case, but the abduction of Israeli soldiers is an emotional issue in a society in which almost every Jewish family has a connection to the military. Israeli Jews are required to do military service from 18. Hundreds of thousands remain liable for reserve duty for years afterwards.
Combat units are required to do everything possible to avoid capture. The "Hannibal directive" was drawn up in 1986 following the capture of two soldiers in Lebanon. It stated: "At the time of a kidnapping the main mission becomes forcing the release of the abducted soldiers from their kidnappers, even if that means injury to our soldiers."
Ten days into the latest Gaza war, Hamas claimed to have captured an Israeli soldier during heavy fighting in Shujayieh in east Gaza City. But the army said later that he was presumed dead. The possibility remains that Palestinian fighters may be holding his remains for another bout of bargaining between unequal but bitter enemies.