New Jersey Sen. Cory Booker (D) was photographed Friday afternoon at the far-left Netroots Nation conference holding an anti-Israel sign calling for the removal of security borders between Israel and the Palestinian territories.

Now, Booker's office is backtracking after the picture garnered attention on social media.

What are the details?

A picture of Booker holding the sign, which declares — "From Palestine to Mexico, all the walls have got to go" — circulated on social media Friday. In the picture, Booker is standing next to anti-Israel activists from the U.S. Campaign for Palestinian Rights, according to the Washington Free Beacon.

The Free Beacon reported that the U.S. Campaign for Palestinian Rights supports the removal of security barriers in Israel and the radical "Boycott, Divest, and Sanction" movement, a global campaign that accuses Israel of apartheid and urges various boycotts against Israel.

It was also recently revealed the group has financial ties to Hamas, Palestinian Islamic Jihad and the Popular Front for the Liberation of Palestine, according to the Times of Israel. The U.S. government designates all three organizations as terrorist groups.

What did Booker's office say?

Considering the Democratic lawmaker has been largely pro-Israel and supportive of Jewish causes, the picture left many confused. However, according to Booker's spokesman, Jeff Giertz, there's a good explanation for the photo.

Giertz said Booker was in a rush when he joined the group for the photo and believed the sign was making a statement about Mexico, not Israel.

"Just before delivering a speech in New Orleans, Senator Booker was approached by dozens of people for photos," Giertz said, according to the Jewish Telegraphic Agency.

"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," he explained.

Giertz also reaffirmed Booker's support for Israel, but added the former Newark mayor longs for the day when security barriers are no longer necessary.

"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 said.