JERUSALEM - Israel was in security lockdown Friday for the Jewish fast of Yom Kippur, which is coinciding with the Muslim festival of Eid al-Adha for the first time in three decades.
The Israeli army said it had sealed off the occupied West Bank from Thursday night to Saturday night for the solemn holiday.
During Yom Kippur, which begins at sunset Friday and lasts for 25 hours, all work, traffic, and TV and radio broadcasts will halt.
Palestinians will only be allowed into Israel for humanitarian reasons or for emergencies.
Israel shuts its borders to Palestinians during its main holidays, citing the increased risk of militant attack as large numbers of Jews congregate for worship.
This year there are also concerns of potential friction within Israel on Saturday when Israeli Muslims celebrate the major feast of Eid al-Adha as Jews fast and pray for Yom Kippur.
The concurrence of the holy days has not occurred for 33 years because the two faiths use different lunar calendars.
This time it follows a 50-day conflict in and around Gaza that killed nearly 2,200 Palestinians and more than 70 Israelis, ending with a ceasefire on August 26.
Police said they were deployed in strength throughout Israel, particularly at synagogues, which attract large crowds over the holy day.
In the mixed northern Israeli town of Acre the two communities have agreed a compromise whereby Muslims will celebrate and feast on Sunday, but from Saturday small electric cars will be provided for those wishing to go to the mosque to pray.
The almost silent electric cars are seen as less likely to upset religious Jews.
The walled old city of Acre will be closed to all traffic.
Riots erupted in Acre on Yom Kippur in 2008 when an Arab resident drove through an observant Jewish neighbourhood blaring music from his car stereo.
On Friday public transport will stop running by 3:00 pm (1200 GMT) and Israel's airspace will be closed from 2:00 pm, public radio said.
Seaports and land borders with Jordan and Egypt will also shut down.