CAIRO — Again and again over decades, Egypt has leapt in to play the role of mediator during hostilities between the Palestinians and the Israelis, including the time two years ago when Egypt’s president, Mohamed Morsi, helped broker a cease-fire after eight days of bloodshed in the Gaza Strip.

But in the latest battle, the Egyptians appear to be barely lifting a finger, leaving the combatants without a go-between as the Palestinian death toll mounts.

Officials with Hamas, the Palestinian Islamist movement in Gaza, said on Wednesday they had seen almost no sign of an Egyptian effort to defuse the crisis, in sharp contrast to previous conflicts under Mr. Morsi and President Hosni Mubarak. Making matters worse, according to Palestinian officials, Egypt continued to keep its side of the border all but sealed on Wednesday, barring even humanitarian aid.

Egypt’s apparent willingness to sit out the crisis reflected shifts in its foreign policy under its new president, Abdel-Fattah el-Sisi, who led the military ouster last summer of Mr. Morsi, a leader of the Muslim Brotherhood and a close ally of Hamas. The Brotherhood was outlawed after Mr. Morsi’s ouster, and accused by Egyptian officials of terrorism during a crackdown on the government’s opponents. In various plots against Egypt described by the authorities, Hamas was often cast as the Brotherhood’s menacing accomplice.