Thousands of Palestinians are gathering in the Gaza Strip to mark the anniversary of the start of protests along the boundary fence with israel.
At least 189 Palestinians and one Israeli soldier were killed between March and December 2018, the UN says.
The rallies backed the declared right of Palestinian refugees to return to ancestral homes in what is now Israel.
A UN inquiry says Israeli soldiers may have committed war crimes during the marches – a charge Israel rejects.
This day of protests will be a serious test of the fragile calm between Israel and Hamas, the Islamist group that runs Gaza, says the BBC's Yolande Knell in Jerusalem.
Egypt and the UN have been negotiating to try to prevent a further escalation after a tense week in which Palestinian militants fired rockets at Israel and Israel's air force struck dozens of sites in Gaza.
With large crowds expected near the fence, Israel has deployed extra soldiers, including snipers.
Previous demonstrations have turned violent with Gazans throwing stones and petrol bombs at Israeli troops.
Israel's military says it only opens fire to stop Palestinians crossing into Israeli territory and protect Israeli civilians.
Palestinian health officials say one man was shot dead by Israeli troops close to the fence overnight.
