An Israeli rabbi has given his blessing to female agents of Israel's foreign secret service, Mossad, who may be required to have sex with the enemy in so-called "honey-pot" missions against terrorists.

Rabbi Ari Shvat's ruling appeared in a study, "Illicit sex for the sake of national security," published by the Tzomet Institute, which studies the interface between religion and modernity.

But Schvat wrote that honey-pot missions are not just a thing of modern-day espionage - such as the late 1980s capture of Mordechai Vanunu, the Israeli nuclear technician who revealed details of Israel's nuclear program, or the January 2010 assassination of terrorist Mahmoud al-Mabhouh in Dubai. Both cases reportedly involved a Mossad female lure.

In fact, honey-pot missions are rooted in Biblical lore.

Queen Esther, who was Jewish, slept with the Persian king Xerxes around 500 BC to save her people, Schvat noted. Yael, wife of Hever, slept with the enemy chief of staff Sisra to tire him and cut off his head, according to tradition.

There is a catch, however, for married honey-pots. "If it is necessary to use a married woman, it would be best [for] her husband to divorce her. ... After the [sex] act, he would be entitled to bring her back," Schvat wrote.

"Naturally, a job of that sort could be given to a woman who in any event is licentious in her ways."

Male agents in Mossad apparently have no limitations on sleeping with the female enemy, as they were not mentioned in the writings.

Schvat's study was praised by Tzomet's director, Rabbi Yisrael Rosen, who added that "women employees of the Mossad are probably not going to come consult with a rabbi" before their missions.