(CNN) Saudi Arabia detained seven activists, including two US citizens, on Thursday, sources tell CNN. It was the kingdom's first sweep of arrests targeting dissidents since the killing of journalist Jamal Khashoggi last year.

A State Department official confirmed to CNN on Friday that two US citizens were arrested in Saudi Arabia, but declined to provide names.

"We can confirm that two US citizens were arrested in Saudi Arabia," the official said. "We have already engaged the Saudi government in this regard. Due to privacy considerations, we have no further comment."

Salah al-Haidar, a dual Saudi-US citizen who is the son of prominent women's rights defender Aziza al-Yousef , was one of those arrested, according to two sources familiar with the events. Yousef was temporarily freed from a prison in Riyadh last month and is on trial along with 10 other women's rights defenders.

One source is a Saudi academic in a US university who has strong relations with the Saudi dissident community. The other source is a Saudi activist with knowledge of the events.

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