The United States plans to announce more than $8 billion worth of military assistance for Ukraine on Thursday during Ukrainian President Volodymyr Zelenskyy's visit to Washington, two U.S. officials said on Wednesday.

President Joe Biden's administration has been engaged in urgent discussions with Congress to allow it to use up $5.6 billion in military aid for Ukraine before Sept. 30 - the end of the federal fiscal year - when the authority was set to expire.

A second announcement slated for Thursday will be for $2.4 billion worth of aid under the Ukraine Security Assistance Initiative program, which allows the administration to buy weapons for Ukraine from companies rather than pull them from U.S. weapons stocks.