U.S. officials said on Wednesday that Ukraine has for the first time begun using long-range ballistic missiles secretly provided by the United States, striking a Russian military in Crimea last week and Russian forces in another occupied area overnight.

According to Ukrainian leaders, the new missiles give Ukraine nearly double the astonishing range - up to 300 kilometers (190 miles) - that it had with the medium-range version of the weapon it received from the United States last October.

One official said that the United States is providing more of these missiles in a new military assistance package signed by President Joe Biden on Wednesday.

One official added that Biden approved the delivery of the long-range tactical missile system for the army, known as ATACMS, in early March, and the U.S. included a "significant" number of them in a $300 million aid package announced at that time.

The two U.S. officials, who spoke on condition of anonymity to discuss the delivery before it was announced, did not provide the exact number of missiles delivered last month or in the latest aid package, which totals about $1 billion.

Ukraine has had to ration its weapons and faces increasing Russian attacks, and Ukraine has been pleading for the long-range system because the missiles provide a critical capability to strike farther Russian targets, allowing Ukrainian forces to remain safely outside range.

Information regarding the deliveries has remained so tightly contained that lawmakers and others in recent days have called for the United States to send the weapons - without knowing they were already in Ukraine.