Sen. Cory Booker (D-N.J.) was seen posing with a sign featured by a pro-BDS Palestinian group.

Booker, a rumored 2020 Democratic presidential hopeful, is seen holding a sign that reads “From Palestine to Mexico, all the walls have got to go,” a slogan developed by the U.S. Campaign for Palestinian Rights.

According to the watchdog group NGO Monitor, “USCPR is a national coalition of hundreds of groups working to advocate for Palestinian rights and a shift in U.S. policy, and is a leader and mobilizer of anti-Israel BDS campaigns.”

USCPR posted the picture of Booker on its Twitter page on Friday.

“Excited to be here at Netroots Nation talking with progressives like Sen. Cory Booker about our shared commitment to freedom, justice and equality for all people,” the tweet said.

Booker, who represents a state with one of the largest Jewish communities in America, has long fostered ties with the Jewish community, and is noted for his study of Jewish texts during his time at Oxford University. However, he has drawn the ire of some within the pro-Israel community in recent years for his support of the Iranian nuclear deal.

In a statement to JNS, Booker’s communication’s director, Jeff Giertz, said that the senator did not realize the sign had to do with Israel when he posed for the picture.

“Just before delivering a speech in New Orleans, Senator Booker was approached by dozens of people for photos. In one instance, amid the rush, he was posing for a photo and was passed a sign to hold — he didn’t have time to read the sign, and from his cursory glance he thought it was talking about Mexico and didn’t realize it had anything to do with Israel,” Giertz said.

“He hopes for a day when there will be no need for security barriers in the State of Israel, but while active terrorist organizations threaten the safety of the people living in Israel, security barriers are unfortunate but necessary to protect human lives,” Giertz added.