The administration of US President Donald Trump took the unusual step of warning the Ukrainian government that its strikes on a Russian Black Sea oil facility late last year had impacted US investments in Kazakhstan, the Ukrainian ambassador to the US revealed Tuesday, CNN reports.

“We have been hearing that Ukrainian attacks to Novorossiysk affected some of the American investments which are being performed through Kazakhstan. And we have heard from Department of State that we should refrain from, from, you know, attacking American interests,” Ambassador Olha Stefanishyna said at a briefing.

Stefanishyna said she had received a demarche, which is a formal diplomatic notice, from the US State Department over the matter. 

The Ukrainian ambassador said the US did not suggest Kyiv should refrain from attacking Russian military and energy infrastructure.

“It was related to the very fact that American economic interest was affected there,” she said. “We have taken the note on that.”

The ambassador noted that the missive from the State Department underscored that US does not currently have the same economic interests in Ukraine as it does in Kazakhstan.

“I was really, really sorry that in 35 years of Ukraine independence, having so many chances, we never brought ourselves to the situation where we can do the same,” she told reporters Tuesday.

Stefanishyna decried what she called a lack of political pressure and failure to give Kyiv the heavy weapons it asked for at the outset of the war in 2022, saying it had allowed Russia to continue to develop.

“Because of lack of sanctions, lack of pressure, lack of commitment, in terms of military systems, we were doing enough for Ukraine to survive, but we were not doing enough for Russia not to evolve,” she said.

Stefanishyna called on US lawmakers to pass legislation to increase sanctions on Moscow, saying that a delay in its passage is seen as a win for Moscow.

“It should be either passed now or we will just have to recognize that there’s no will to do it,” she said.

“If we are able to impose more sanctions and more pressure on Russia, they will not be in a position to withdraw from the negotiations,” she added.

In late November, Ukrainian drones struck the Black Sea port of Novorossiysk, damaging not just Russian interests but also a key pipeline, which led to a significant drop in Kazakh oil exports.

The American company Chevron is a major shareholder in the Caspian Pipeline Consortium, which carries oil from Kazakh oil fields to the Black Sea for export.