Israel's army said it was extending the closure on the West Bank and Gaza due to a manhunt for six Palestinian escapees who tunneled their way out of jail earlier this week.
"In an effort to locate the escaped prisoners, it has been decided to extend the general closure," an Israeli military spokesperson said in a statement on Wednesday night.
It said the closure, originally planned to end on Wednesday midnight, will now continue until Saturday night.
Lifting the closure will be "subject to a situational assessment", the statement added.
The crossings for the transfer of goods into the Gaza Strip and the West Bank opened as planned on Wednesday.
However, all of the other crossings will remain closed and Palestinians could pass through them only "under special or medical circumstances and on a humanitarian basis".
The closure has been imposed on Monday afternoon, right before the Jewish New Year.
Israel considers the main Jewish holidays as prone to attacks by Palestinian militants and regularly closes off the occupied territories during these times.