WASHINGTON (Reuters) - The United States said on Thursday it was concerned about reports of detentions, beatings and other abuses targeting opposition activists in Zimbabwe, including the return by Zambia of opposition leader Tendai Biti to Zimbabwean authorities.

“We will be discussing this matter with Zambia’s leaders and reviewing certain aspects of our cooperation with the Zambian government,” the State Department said in a statement. The United States summoned the ambassadors of both countries in Washington to express their concerns.