Israel shut crossings into the occupied West Bank on Friday and reinforced patrols along its borders with Lebanon and Syria to try to thwart pro-Palestinian rallies around the country.
Palestinian activists have called for a "Global March to Jerusalem" to coincide with annual Land Day demonstrations by Israel's Arab minority, and say there will be protests in numerous locations to denounce Israeli settlement policy.
Israeli officials say they want to avoid a repeat of violence that flared last May, when its forces opened fire as hundreds of protesters surged towards its borders from Lebanon and Syria, killing several people.
"Forces are deployed widely around the country and they are on alert," Israeli Police Minister Yitzhak Aharonovitch told Army Radio. The army announced West Bank crossings would remain shut until midnight on Friday.
Palestinian organisers have said they want to stage peaceful rallies to protest against "the policies and practices of the racist Zionist state".
Land Day commemorates the killing by security forces of six Arabs in 1976 during protests against government plans to confiscate land in northern Israel's Galilee region.
Previous remembrances have mostly passed quietly, but Israel decided to reinforce its defences following the deadly clashes last year that appeared to catch the military off guard.
An Israeli army officer told Reuters the Golan ceasefire line with Syria had been fortified with a new fence and land mines, and that violence on last year's scale was unlikely.
The army also said that U.N. peacekeepers had toured its Lebanese border last week, viewing Israel's deployment and relaying plans by Lebanon's military to rein in any protests on their side of the fence.
In Jerusalem, police barred men younger than 40 from attending Friday prayers at the holiest Islamic shrine in the city, the al-Aqsa Mosque, police spokesman Micky Rosenfeld said.
Jerusalem is a focal point of conflict, as Palestinians want the city's eastern sector captured by Israel in a 1967 war as capital of a future state. Israel has annexed East Jerusalem as part of its capital and insists the city remain united.
Israel is wary of possible violence with peace talks stalled for months and Palestinian leaders refusing to return to the negotiating table until Israel halts all Jewish settlement building in the West Bank.
Leading Palestinian activist Marwan Barghouti, serving multiple life sentences in an Israeli jail for orchestrating suicide attacks, called on Monday for a new wave of civil resistance in the decades-long quest for statehood.
On high alert along its borders, police were also wary of possible friction within the boundaries of Israel, where the Arab minority was planning protests.
Arabs make up about a fifth of Israel's total population. Many complain of discrimination. Israeli Prime Minister Benjamin Netanyahu has recently called for improved efforts to integrate Arab citizens into Israel's work force.