(JTA) — A US official accused Israel of treating some Arab Americans unequally after the Jewish state detained and denied entry into its borders five pro-Palestinian American activists.

State Department spokesman Mark Toner on Tuesday reiterated the United States’ “concern” about “unequal treatment” following reports of the July 17 incident at Ben Gurion Airport.

Upon their arrival on July 17, a U.S. staffer for the organization US Campaign to End the Israeli Occupation and four other members of the group — all carrying US passports — were “interrogated by Israeli border police about their backgrounds and political involvement,” according to a statement issued by the organization Tuesday.

Four of the five were “people of color and Muslim” and the fifth had a long beard, the group added. Americans do not need visas to enter Israel. The group is a supporter and promoter of the campaign to boycott Israel and all Israeli products.

American officials were aware of reports on the incident but could not get into details because of “privacy considerations,” Toner told journalists Tuesday, according to NBC News.

“The US government remains concerned about unequal treatment that some Arab-Americans receive at Israel’s borders and checkpoints,” he added. “And we regularly raise with Israeli authorities our concerns about the issue of equal treatment for all U.S. citizens in ports of entry.”

A spokesman for Israel’s Interior Ministry told NBC that three of the five campaigners were denied entry for “security reasons” but did not elaborate on what those reasons were. End the Israeli Occupation did not provide the names of two of the activists so Israeli officials could not provide information on their attempts to enter.

The delegates, who included Bina Ahmad, a New York City public defender, were denied entry into Israel and then detained for hours before they were sent back to the United States.

Calls to the US Consulate “resulted in no assistance for the delegates,” according to the organization.

At a press briefing in March of 2014, State Department spokesperson Jen Psaki stated that “the Department of Homeland Security and State remain concerned with the unequal treatment that Palestinian Americans and other American of Middle Eastern origin experience at Israel’s border and checkpoints, and reciprocity is the base basic condition of the Visa Waiver.”

Israel has a visa waiver arrangement with the European Union, the United Kingdom, Japan, Russia and dozens of other countries. However, Israelis need to apply for a visa to enter the United States.