(AFP / Voz Media) The Houthi rebels in Yemen justified the arrest of nearly two dozen aid workers in a statement, accusing them of espionage.

In fact, the terrorist group claims to have dismantled a "spy network." The Houthis claim that "an American-Israeli spy network was arrested," in a statement published by their security agency, and specified that those detained were working under "the cover of international organizations and U.N. agencies."

The United Nations confirmed on Friday that 11 of its employees were among those captured and called for their release. "We're pursuing all available channels to secure the safe and unconditional release of all of them as rapidly as possible," U.N. spokesman Stéphane Dujarric said at the time.

According to the Yemeni human rights organization Mayyun, at least 18 Yemenis were kidnapped last Thursday.

The arrests were "simultaneous," according to the NGO, and took place in Sanaa, the capital, and the cities of Hodeida, Amran and Saada, a traditional stronghold of the rebels.

The United States began attacking Houthi targets in Yemen in January in response to the group's continued attacks on vessels in the Red Sea. The Houthis claim that they began the offensives to defend the Palestinian cause when the war in Gaza started, although behind these intentions some analysts see an attempt to gain legitimacy within their prolonged civil war.