WASHINGTON, Sept 25 (Reuters) - The United States plans to announce more than $8 billion worth of military assistance for Ukraine on Thursday during Ukrainian President Volodymyr Zelenskiy’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.

On Thursday, U.S. officials said, the White House intends to notify Congress it will move forward with the announcement of a $5.6 billion drawdown from U.S. weapons stocks. The contents of that package are still in flux, the officials said.

Reuters reported this month that the Biden administration was considering a backup plan under which it would announce plans for shipments for Ukraine, but with an extended delivery timeline for the weapons and equipment, allowing for a more gradual transfer of resources to Ukraine without missing the Sept. 30 deadline.

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. stocks.

That aid will include munitions, weapons to combat drones and material to support munitions production in Ukraine, one of the U.S. officials said.

In addition, the U.S. announced on Wednesday $375 million worth of Presidential Drawdown Authority for Ukraine. The package will include the first shipment of a precision-guided glide bomb with a range of up to 81 miles (130 km) called the Joint Standoff Weapon, two U.S. officials said. The inclusion of that weapon was not disclosed in the announcement.