BURLINGTON, Vt., June 22 – Sen. Bernie Sanders (I-Vt.) and five of his Senate colleagues urged Secretary of State Mike Pompeo in a letter to address the detention of human rights activists in Saudi Arabia.

At least three women’s rights activists and three men associated with the women’s rights movement are currently detained, and four other women’s rights activists have been arrested and released since May 15. The Saudi government has accused the detained activists under thin pretenses of “suspicious contact with foreign parties” and “undermining security and stability” of the state.

“Support for human rights has long been a cornerstone of American foreign policy. These blatant rights violations on the part of a close ally reflect extremely poorly on the United States. As such, we urge you to communicate these concerns to the Saudi government,” the senators wrote in the letter.

The detainments come at a time when Saudi Arabia has initiated reforms, including ending the kingdom’s ban on women drivers, and coincided with Saudi Crown Prince Mohammed bin Salman’s visit to the United States, where he offered support for women’s rights reforms in an interview on CBS’ “60 Minutes.”

State Department spokeswoman Heather Nauert said in May that the administration is “keeping a close eye” on Saudi Arabia’s proposed reform program, but neither Pompeo nor the State Department has taken up the arrests with Saudi authorities or condemned the persecution of activists.

“It is clear that the Saudi government is still cracking down on activists and bloggers, including those who support women’s rights and are seen as pushing for too much, too quickly,” the senators wrote.

In addition to Sanders, the letter was signed by Sens. Robert Casey (D-Pa.), Richard Durbin (D-Ill.), Kirsten Gillibrand (D-N.Y.), Tim Kaine, (D-Va.) and Mark Warner (D-Va.).

To read the letter, click here.