HARARE, Zimbabwe (AP) — The United States State Department said Friday that Zimbabwean authorities detained officials of the U.S. development agency, USAID, before deporting them, as relations between the historical foes deteriorate further.

State Department spokesperson Matthew Miller said Zimbabwean officials “abruptly detained and deported USAID officials and contractors, who were conducting an assessment of the development and governance context in Zimbabwe.”

Last week, the U.S sanctioned Zimbabwe’s President Emmerson Mnangagwa, its first lady and other officials for their alleged involvement in corruption and human rights abuses.

The State Department said the incident took place last month, before the latest round of sanctions was announced, although it was only revealed now.

The Zimbabwean government and its ruling Zanu-PF party have frequently accused the U.S of interfering in the country’s internal political affairs to effect regime change after Mugabe led an often violent land reform program that drove out white farmers who owned most of the fertile agricultural land to make way for thousands of landless Back Zimbabweans.

Miller said members of the assessment team “were subject to aggressive handling, prolonged interrogation and intimidation, unsafe and forced nighttime transportation, overnight detention and confinement, and forced removal from the country.”

In a separate statement, USAID administrator Samantha Power accused the Zimbabwean authorities of “seizure of and intrusion into personal electronic equipment” of the officials and some contractors.

Zimbabwean foreign affairs authorities as well as U.S embassy officials did not respond to requests for comment.

Relations between the two countries have been icy since Washington imposed sanctions on the southern African country more than two decades ago over allegations of human rights abuses.

Mnangagwa promised democratic reforms and made engagement with the U.S a priority when he replaced longtime ruler Robert Mugabe after a popular army-backed 2017 coup. But he is now accused of being as repressive as his predecessor and mentor.

Miller said the actions of the Zimbabwean authorities “undermine” Mnangagwa’s claims of re-engagement, adding that “we take the safety and security of U.S. citizens seriously and demand accountability from the Government of Zimbabwe.”

President Joe Biden signed an executive order last week that terminated the use of emergency powers, which had been in place since 2003, to impose sanctions on Zimbabwe over alleged human rights abuses.

Simultaneously, the Treasury’s Office of Foreign Assets Control imposed sanctions on three entities and 11 people, including the Mnangagwas and Vice President Constantino Chiwenga, a powerful political figure who led Mugabe’s ouster as military general before being appointed to his current post.

Mnangagwa described the U.S. measures as “absolute nonsense” and called for the sanctions to be lifted “in their entirety.”

Despite strained political relations, USAID has remained one of Zimbabwe’ biggest donors in ailing sectors such as health and agriculture.

But its human rights programs have constantly attracted criticism from the Zimbabwean government, which frowns at perceived close links between USAID and Zimbabwean non-governmental organizations involved in good governance campaigns.