Israel ? An Israeli couple, joined by a young woman reported to be their daughter, entered one of Christianity’s holiest sites Friday and set off a series of small explosions, sparking a riot that left six people wounded in Nazareth.

The family’s motives were unclear, but police said the couple had been treated for psychiatric problems in the past and faced the possibility of losing custody of their children.

Although the attack did not appear to be nationalistic, it underscored the tensions between Israel’s Jewish majority and its Arab minority. Israeli Arabs, who make up about 20 percent of the population, complain of systematic discrimination.

Police said the three entered the Basilica of the Annunciation Friday evening and set off firecrackers and other small explosives. Church officials said the site was unguarded, and witnesses said the explosives were hidden in a baby stroller.

Within minutes, thousands of people began rioting outside.