Israeli forces have killed a Palestinian man and a teenage boy and wounded 33 protesters, according to Palestinian medical officials.
The protests mark the first anniversary of the often violent weekly border demonstrations in which over 250 Palestinians have been killed.
They also come just 10 days before a keenly contested general election in Israel.
The demonstrators are calling for Palestinians to be allowed to return to land their families fled in the 1948 war that accompanied the creation of Israel.
Demonstrations are expected to peak on Saturday afternoon.
Several thousand troops, including dozens of snipers, are positioned at various locations along the border.
Palestinians and human rights organizations accuse Israel of excessive use of force.
Source: Palestine Chronicle