WASHINGTON, May 3 (Reuters) - The United States said Wednesday it would send a new military aid package for Ukraine worth $300 million, including for the first time the Hydra-70 short-range. air-launched rocket, taken from U.S. excess stocks.

The security assistance package would be the 37th approved by the United States for Ukraine since Russian invaded its neighbor in February 2022, for a total of $35.7 billion.

"The United States and our allies and partners will stand united with Ukraine, for as long as it takes," U.S. Secretary of State Antony Blinken said in a statement announcing the aid package.

The rockets, munitions and 155mm howitzer cannons included in the package would help Ukraine weaken Russian ground positions for advancing Ukrainian ground forces as Kyiv plans a spring offensive.

The Hydra-70 is an air-launched, unguided rocket made by General Dynamics Corp (GD.N). The rockets are typically launched from pods attached to aircraft to provide support for ground troops.

The package also includes AT-4 and Carl Gustaf anti-tank weapon systems, TOW anti-tank missiles, several sizes of mortars, and High Mobility Artillery Rocket System (HIMARS) munitions.

Demolition equipment and trucks are also part of the package as well as diagnostic equipment to maintain vehicles.

The package would be funded using Presidential Drawdown Authority, which authorizes the president to transfer articles and services from U.S. stocks without congressional approval during an emergency.