Secretary of State Rex Tillerson’s decision to warn African countries that Chinese investment can undermine sovereignty was “not appropriate,” according to Russia’s top diplomat.

“It was not appropriate to criticize the relations of his hosts — when he was a guest there — with another country,” Russian Foreign Minister Sergey Lavrov told reporters Thursday.

That scolding follows a minor dispute about whether Tillerson and Lavrov would meet in Ethiopia, where their respective travels through several African nations intersect Thursday. Tillerson attributed the missed connection to a tight-schedule and a last-minute request, though Russia disputed that account. He worked instead to affirm U.S. commitment to the region, despite Trump’s reported disparagement of Africa, and that involved warning against excessive dependence on investment from the Chinese government.

“We are not in any way attempting to keep Chinese investment dollars out of Africa,” Tillerson said. “They are badly needed. However, we think it’s important that African countries carefully consider the terms of those investments, and we witness the model that the Chinese follow ... oftentimes, the financing models are structured in a way that the country, when it gets into trouble financially, loses control of its own infrastructure or its own resources through default.”

Tillerson has dubbed this “predatory economics,” a growing concern for U.S. officials who see Chinese using economic relationships as a point of leverage in foreign policy. Notably, Tillerson plans to visit Djibouti, a tiny country in East Africa that controls a strategically significant port. Pentagon officials worry that China might take the port as repayment of $1.2 billion debt owed by the Djiboutian government.

“If the Chinese took over that port, the consequences could be significant if there were some restrictions on our ability to use that, because obviously the supplies that come in not only take care of Camp Lemonnier and other places inside the continent, it is a huge activity there,” Gen. Thomas Waldhauser, head of U.S. Africa Command, told the House Armed Services Committee during a Tuesday hearing.

That’s the part of the context for Tillerson’s warning. “Our message is for countries to consider carefully what the terms of those agreements are, and not forfeit any elements of your sovereignty as you enter into such arrangements with China,” he said.

Lavrov took a dig at Tillerson’s remarks nonetheless. "I did not know that Rex Tillerson was an expert on the Chinese-African relations,” he jibed.