A forthcoming trip to Israel and the Palestinian territories by Reps. Ilhan Omar (D-Minn.) and Rashida Tlaib (D-Mich.) will possibly be blocked by Israel in its current proposed format, a senior Israeli government official told The Washington Post on Thursday.

Speaking on condition of anonymity because of the sensitivity of the matter, the official said that if Tlaib, an American of Palestinian heritage, made a special humanitarian request to visit her family in the occupied West Bank, then “it would be considered favorably.”

Omar and Tlaib, who have both been outspoken critics of Israel and support a boycott movement against the country, are slated to arrive Sunday. Their trip is being planned by Miftah, a nonprofit organization headed by Palestinian lawmaker and longtime peace negotiator Hanan Ashrawi.