US congresswoman Rashida Tlaib is of Palestinian origin.

Israel is to allow a visit by barred US congresswoman Rashida Tlaib who is of Palestinian origin on "humanitarian" grounds, the interior ministry announced Friday.

It said Interior Minister Aryeh Deri decided to allow Tlaib to make a "humanitarian visit to her grandmother" in the Israeli-occupied West Bank after the lawmaker had sent him a written pledge "to respect conditions imposed by Israel".

Tlaib had "promised not to promote the cause of the boycott of Israel during her stay", in a letter to Deri sent overnight, the ministry said in a statement.

Israeli media published the letter reading: "I would like to request admittance to Israel in order to visit my relatives, and specifically my grandmother, who is in her 90s...

"This could be my last opportunity to see her. I will respect any restrictions and will not promote boycotts against Israel during my visit."

On Thursday, Israel announced it would bar a planned visit by Tlaib and fellow Muslim congresswoman Ilhan Omar over their support of a boycott of the Jewish state for its treatment of the Palestinians.

Israeli officials had, however, said they would consider a separate humanitarian request from Tlaib to visit her family, a trip for which she would have to pass through Israel.

The decision to bar the congresswomen, although encouraged by President Donald Trump, drew sharp criticism in the United States from several allies of Israel, including top Democratic lawmakers, presidential hopefuls and influential pro-Israel lobby AIPAC.

Omar and Tlaib had been expected to arrive in Israel at the weekend.

Before Israel announced its decision, relatives of Tlaib in the West Bank village of Beit Ur Al-Foqa had been excited about her planned visit.