Palestinian President Mahmoud Abbas declared Friday a day of mourning for the victims, who he described as ``martyrs of trying to make a living.'' Thousands of Palestinian laborers work in Jewish settlements along Highway 90, which runs through the Jordan Valley.

Videos circulating online appeared to show the truck slamming into the van head-on as the van sought to make a left turn off the highway.

Israel's Magen David Adom rescue service confirmed the seven deaths and said three people were evacuated by military helicopter for medical treatment, including an 18-year-old and a 20-year-old in critical condition.

Israel captured the West Bank in the 1967 war, and Palestinian want it to form the main part of their future state.

Tens of thousands of Palestinians work in Israel and Israeli settlements, where wages are much higher than in the parts of the West Bank administered by Abbas' Palestinian Authority. The economic disparity largely stems from Israel's 54-year occupation of the territory and the restrictions it imposes on the more than 2.5 million Palestinians living there.

The Palestinians and most of the international community view the settlements, home to nearly 500,000 Jewish settlers, as illegal and an obstacle to resolving the decades-old conflict.