JERUSALEM — An Israeli security guard shot and killed a Jewish man at the back of the Western Wall plaza early Friday after apparently suspecting him of being a Palestinian militant about to carry out an attack, the police said.

Tensions occasionally run high around the holy site where throngs of Jewish worshipers regularly pray before the huge beige stones, a remnant of the retaining wall of the Temple Mount revered by Jews as the site where their ancient temples once stood.

On the plateau above the wall, Muslims pray at Al Aksa Mosque, the third holiest site in Islam. Like the wall, the mosque compound, known to Muslims as the Noble Sanctuary, is in the Old City of Jerusalem, a fiercely contested area captured by Israel from Jordan in the 1967 war, and Israeli-Palestinian clashes erupt there from time to time.

Micky Rosenfeld, a spokesman for the police, said that based on the initial testimony of the security guard, the shooting victim, who was identified as Doron Ben-Shlush, 46, had shouted “Allahu akbar,” or “God is great,” and had his hand in his pocket at the time he was shot, near a public restroom at the back of the plaza. The guard, from a private firm contracted to secure the entrances to the plaza, fired several shots at the man, who was pronounced dead at the scene. The guard, who was arrested, was ordered held in court later Friday.