Israeli forces detained U.S. Democratic congressional candidate Brad Lander on Wednesday as he helped Palestinian farmers harvest olives in the occupied West Bank, releasing him hours later while dozens of other volunteers, including a group of American rabbis, remained in custody.

The incident was the latest in an annual olive harvest that has been marked by violence between Israeli settlers and Palestinian villagers attempting to gather their crops.

The Israeli military said the farmers and volunteers had failed to seek prior approval for the harvest and were detained "due to the security risk posed by conducting an uncoordinated harvest near an Israeli community." It later added that it viewed "the arrival of dozens of activists as an act intended solely to provoke, which undermines the harvesting process." Lander is running in the U.S. elections on Nov. 3 to represent a heavily Democratic New York district in the U.S. House of Representatives.