Emad Hajjaj was arrested Wednesday after publishing a cartoon depicting the leader of the United Arab Emirates holding a dove with an Israeli flag on it that has spit in his face. The spit is labeled F-35, a reference to Israel's opposition to the sale of advanced US aircraft to the Emirates following the US-brokered deal.

Nidal Mansour, the founder of a press freedom center in Jordan, said Friday that Hajjaj was referred to a State Security Court and is being investigated for harming relations with a friendly state.

Jordanian authorities have not commented publicly on the case.

Jordan is a close Western ally and one of only two Arab nations to have signed a peace treaty with Israel. The UAE, which does not share a border with Israel and has never gone to war with it, would be the third Arab country to normalize relations.

"The continued detention of a well-respected cartoonist and the legal chaos reflects Jordan’s difficult position of trying to balance its relations with the oil-rich emirates with the rights of its own citizens to express themselves," said Daoud Kuttab, a Palestinian journalist based in Jordan who has closely followed the case.

The International Press Institute, of which Kuttab is an executive board member, and the New York-based Committee to Protect Journalists, have called for his release.

"Journalists and cartoonists like Emad Hajjaj are entitled to express their views freely on the Israel-United Arab Emirates deal, which affects the lives of millions of people across the region," said CPJ’s Middle East and North Africa representative, Ignacio Miguel Delgado.

"Jordanian authorities should immediately release Hajjaj, drop all charges against him, and allow him to provide political commentary without fear of imprisonment."

The UAE agreement with Israel came under heavy criticism from the Palestinians and their supporters because it broke with a longstanding Arab consensus that recognition should only be granted in return for concessions in the peace process.

The Emirates said the deal had halted Israel's plans to unilaterally annex up to a third of the occupied West Bank, which the Palestinians want for their future state. But Israel has said the pause is only temporary.

The deal could pave the way for the oil-rich UAE to purchase advanced American weaponry, including F-35 stealth fighter jets. Israel is opposed to such sales, even to US allies, fearing they could undermine its military superiority in the region.