Military strategy What are Biden's options in his last weeks in power?

With a little over two months left in the White House, Joe Biden is running out of time to expedite the delivery of funds and weaponry needed to ensure that Ukraine can stay in the fight against the Russian invasion.

- Andrew Roth

The White House is transferring weapons and up to $6bn (£4.6bn) in remaining aid as quickly as possible to Ukraine, while advocates for Kyiv are calling on the White House to repeal restrictions on long-range weaponry and find other sources for funding the war before Donald Trump enters office in January.

Ahead of each presidential transition, administration officials repeat the mantra that they serve "one president at a time", and Biden remains in full control of US foreign policy until Trump's inauguration on 20 January. But the prospect of a step change in Ukraine policy under Trump makes it unlikely that any serious moves by Biden will remain in place under the next administration.

It is unlikely that the administration can push another aid supplemental promising more money through Congress, but there is still $6bn in outstanding aid that can be dispersed before Biden leaves office. After that, US officials have admitted, Ukraine will mainly have to focus on Europe for its support.

The Pentagon has allowed a small number of US defense contractors to work inside Ukraine to maintain and repair F-16 fighter jets and Patriot missile defense systems. And a report by the Wall Street Journal says the Pentagon is speeding up delivery of more than 500 missile interceptors to Ukraine before the end of Biden's term amid concerns that Russia is saving up its own missiles for a massive barrage against Ukrainian cities or energy infrastructure during the winter.

Senior US and European officials had made efforts to "Trump-proof" much of the support for Ukraine, moving the authority for deliveries of weapons to Kyiv to Nato in advance of a potential Trump presidency.