The Russian Ministry of Foreign Affairs also claimed Wednesday that the Ukrainian government had undertaken "active preparations" for a military offensive in eastern Ukraine, using the recent declaration of martial law in select regions as a cover.
"Substantial offensive components are being transferred to the region, which are being dispersed along the entire contact line," spokesperson Maria Zakharova said Wednesday at a press briefing.
The US is required to notify Turkey about the passage through the straits under the Montreux Convention, a 1936 treaty that governs the passage of military vessels through the Bosporus and the Dardanelles, which connect the Mediterranean to the Black Sea.
Under the rules of the treaty, countries that do not have a coastline on the Black Sea are required to provide Turkey with at least 15 days' notice prior to transiting the straits.
'Prepared to respond'
A State Department spokesman said, "the United States carries out its activities consistent with the terms of the Montreux Convention. We will not, however, comment on the nature of our diplomatic correspondence with the Government of Turkey."
Two of the officials said that the notification was to provide the Navy the option to move a warship into the area, but that this option would not necessarily be selected.
"Our US 6th Fleet is always prepared to respond where called," said Cdr. Kyle Raines, a spokesman for the Fleet, which oversees naval operations in the region.
"We routinely conduct operations to advance security and stability throughout the US 6th Fleet area of operations to include the international waters and airspace of the Black Sea," Raines told CNN. "We reserve the right to operate freely in accordance with international laws and norms," he added.