Israel has barred dozens of Palestinian-Americans from leaving the country following last week's suicide bombing at a Tel Aviv disco, according to the U.S. consulate.

Since Friday night's bombing, the government has refused to allow American citizens who hold a Palestinian identification card — issued to residents of the West Bank and Gaza Strip — to board flights at Ben-Gurion International Airport, U.S. embassy spokesman Larry Schwartz said Tuesday.

Between Saturday and Monday, airlines reported to the U.S. consulate that 160 U.S. citizens were kept from leaving, he said. Figures for Tuesday and Wednesday were not immediately available.

"We're very concerned about American citizens in the region. We plan to raise this case with the Israeli government." said Schwartz.

Residents of the West Bank and Gaza Strip, even those who hold U.S. citizenship, must apply to the Israeli government for exit permits to leave the country. That was also true before the bombing.

No Palestinian exit permits have been issued since the bombing, which killed 21 people, most of them Israeli teenagers. Under the tight closure imposed on the West Bank and Gaza following the explosion, exit permits that had been previously issued were canceled.

Maj. Peter Lerner, a spokesman for Israel's administration in the West Bank, said Wednesday that the restrictions were necessary for security reasons.

"If the relatively calm situation continues, it will be easier to allow Palestinians to travel through Israeli territory to leave the country," he said.

A Palestinian-American human rights lawyer dismissed the Israeli explanation. "It's just a form of harassment," said Jonathan Kuttab, who helps Palestinians secure travel permits from Israel. "It has nothing to do with security or anything else."

The State Department is warning U.S. citizens to defer travel to Israel, the West Bank and Gaza. It also issued a statement giving an additional warning to Palestinian-Americans: "During periods of heightened security restrictions, Palestinian-Americans with residency status in the West Bank or Gaza may not be allowed to enter or exit Gaza or the West Bank, even if using their American passports."