David Cameron insists the UK's commitment to the Nato military campaign in Afghanistan is "undiminished" despite the sacking of commander Stanley McChrystal.
President Barack Obama called the Prime Minister to inform him of the US general's departure, which came after he publicly criticised the American administration.
Downing Street said Nato's British deputy commander in Afghanistan, Lt Gen Nick Parker, would be taking charge temporarily until the appointment of US Gen David Petraeus is cleared by Congress.
A Number 10 spokesman said: "The White House informed Downing Street of the President's decision earlier this evening, while the Prime Minister was in his weekly audience with Her Majesty the Queen.
"The Prime Minister later spoke to President Obama. The Prime Minister and the President again made clear that the UK and US Governments remain absolutely committed to the strategy in Afghanistan.
"They agreed that General Petraeus was the right man to take command."
Lt Gen Parker became deputy commander of the Nato-led International Security Assistance Force (Isaf) in Afghanistan under Gen McChrystal in November.
He praised his former boss and his counter-insurgency strategy just before news of the Rolling Stone article broke.
The British general wrote in The Times: "General Stanley McChrystal's arrival in Afghanistan has brought a new approach and a sense of optimism to the International Security Assistance Force. He has reinvigorated operations by focusing on protecting the population."
