UN human rights chief Navi Pillay was deeply troubled by Israel's attack on Syrian protesters at their shared border Sunday, she said in a press conference today.

Pillay said that Israeli Defense Forces have killed 30 to 40 protesters in the past three week, according to reports.

Last Sunday, 23 protesters were shot and killed by Israeli soldiers when they approached the fence marking the ceasefire line between Syria and Israel.

That protest was organized to commemorate the Naksa, or the Arab loss in the 1967 Six Day War.

Earlier this year, at a May 15 protest commemorating the Nakba, or the 1948 creation of the state of Israel, protesters also tried to bypass the border. Ten Lebanese protesters were killed, and four Syrian protesters were also killed.

After the May 15 protest, Lebanon declared the border with Israel a closed military zone before the scheduled protests last Sunday to prevent any casualties and what, in the case of Syria, has turned into an international incident.

Syria made no moves to prevent protesters from approaching the border. Israel has accused Syrian President Bashar al-Assad of provoking the potential international security breach to distract from the opposition groups' protests raging on the streets of Damascus and around the Levantine nation.

Pillay said that Israel has a duty to avoid the excessive use of force.