ON ROUTE 60, WEST BANK - Four Israelis traveling in a car near the West Bank city of Hebron were shot dead Tuesday night as the Obama administration prepared to host Israeli-Palestinian peace talks in Washington.

One of the four killed was a pregnant woman.

The four passengers were from the Israeli settlement of Beit Hagai near Hebron.

The couple killed, Yitzhak and Taliyah Immas, were immigrants from the former Soviet Union, a person who knew them said. The other two passengers, a man and a woman, were identified as Avishai Shindler and Kochava Even Haim.

The car, a white Subaru station wagon, with roughly 20 bullet holes in it, remained on the highway several hours after the shooting.

The deadly shooting shattered a relative calm that has prevailed for nearly three years in the West Bank as Palestinian security forces have improved their capabilities and asserted more authority in areas under their control.

The calm has led to an easing of Israeli restrictions on Palestinian movement and has improved the climate for a resumption of direct peace negotiations.

Hamas's military wing, the Izzedine al-Qassam Brigades, asserted responsibility for the attack.

Hamas spokesman Sami Abu Zohri said the attack was a "normal reaction" to Israel's "occupation crimes." Daoud Shehab, a spokesman for Islamic Jihad, called it the "first step in causing the negotiations to fail.''

The Israeli army "sees this event severely," army spokeswoman Avital Leibovich told reporters by telephone. She said the army hoped it was an isolated operation.

In June, an Israeli police officer was shot dead on the same road where Tuesday's attack took place. Attacks on civilians have been rare in recent years, however. The last time an Israeli civilian was killed in the West Bank was in December 2009, the army said.

Leibovich declined to confirm reports that the passengers Tuesday were shot at close range following an initial drive-by shooting.

Special correspondent Islam Abdelkarim in Gaza City contributed to this report.