US President Joe Biden confirmed on Thursday that his country will continue coordinating with Britain to support the Ukrainian people and hold Russia accountable.

He said, "I look forward to continuing cooperation with the British government." This came after British Prime Minister Boris Johnson announced his resignation as leader of the Conservative Party, calling for a quick selection of a new leader following immense pressure and resignations from about 59 ministers, deputies, and officials in his government team.

He added in a speech on Thursday that he is "sad to leave the best job in the world," as he put it, listing his government's achievements from Brexit to confronting Russia.

Johnson will continue as Prime Minister until the Conservative Party chooses a new leader in the fall. The British Prime Minister is considered one of the strongest supporters of Ukraine in facing the military operation launched by Russia since February 24.

Days ago, Johnson pledged to provide another £1 billion in military aid to Ukraine, raising the total military and economic support to £3.8 billion this year.

The outgoing Prime Minister also pledged to send the UK more air defense systems and drones, and to put 1,000 British soldiers on alert so they can be quickly deployed. The British government had sent anti-tank missiles, air defense systems, and other weapons to Ukraine.