The United States envoy to South Africa said on Thursday he was confident that a Russian ship had picked up weapons in South Africa last year, in a possible breach of Pretoria’s declared neutrality in the Ukraine conflict.

The rand and South Africa’s 2030 government bond extended losses after the U.S. assertion as currency traders said they were worried that South Africa could now face Western sanctions.

The government is opening an independent inquiry led by a retired judge into the allegation, the office of President Cyril Ramaphosa said in a statement.

Earlier, Ramaphosa did not confirm or deny the shipment took place when an opposition leader asked him about it in parliament.

The U.S. ambassador to South Africa, Reuben Brigety, told local journalists in a briefing that Washington was confident a Russian vessel had uploaded weapons and ammunition from South Africa in December.

“Amongst the things we noted were the docking of the Russian cargo ship Lady R in Simon’s Town between Dec. 6 and Dec. 8, 2022, which we are confident uploaded weapons, ammunitions … as it made its way back to Russia,” Brigety said.

“Arming of Russia by South Africa with the vessel … is fundamentally unacceptable,” Brigety said, adding that senior U.S. officials had “profound concerns” about South Africa not respecting its professed policy of non-alignment and neutrality over Russia’s war in Ukraine.

This “does not suggest to us the actions of a non-aligned country”, he said in a recording of the briefing heard by Reuters.

South Africa is one of Russia’s most important allies on a continent divided over its February 2022 invasion of Ukraine, but says it is impartial on the conflict and has abstained from voting on U.N. resolutions on the war.