JERUSALEM — Israel closed all access to Jerusalem’s most sensitive religious site on Thursday, a rare move that ratcheted up already heightened tensions following the attempted assassination of a prominent Jewish religious activist and the killing of his suspected Palestinian assailant by police.

The Palestinians accused Israel of a “declaration of war,” deepening a crisis fueled by failed peace efforts, continued Israeli settlement construction and months of simmering violence in the holy city. While Israel said it would reopen the site on Friday, the increasingly religious nature of the unrest risked igniting further violence.

Both the Israeli and Palestinian leaders blamed each other for the tensions. Israeli Prime Minister Benjamin Netanyahu accused Palestinian President Mahmoud Abbas, who has called for banning Jews from the hilltop holy site, of inciting the violence.

“The international community must stop its hypocrisy and act against the inciters,” Netanyahu said.

Abbas, meanwhile, said Jerusalem is a “red line that must not be touched.” The decision to close access to the Al Aqsa Mosque compound was “a declaration of war” that “will lead to further escalation and instability,” his spokesman, Nabil Abu Rdeneh, said. Abbas made no mention of the attempted killing of the Jewish activist.

East Jerusalem, the section of the city captured by Israel in 1967 and claimed by the Palestinians, has experienced unrest since the summer, with Palestinian youths throwing stones and firebombs at motorists and clashing frequently with Israeli police. The violence intensified last week, when a Palestinian rammed his car into a crowded train station, killing a 3-month-old Israeli-American girl.