The war in Afghanistan must be spared from financial cuts, the former head of the Army has said.
General Sir Richard Dannatt said it would be "wrong" to "skimp on an operation where lives are at risk and the national interest is at stake".
His comments came as David Cameron made his first visit to the country as prime minister.
Mr Cameron told troops he wanted the British public to "revere and support" them for the "incredible work" they do.
Asked about the possibility of future cuts, Gen Dannatt told BBC Radio 4's Today programme: "The military has got to decide what it really, really needs when, and what we have got to do is to make sure that we properly fund the current operation in Afghanistan.
"If we are going to take any form of risk anywhere it's with our provision for the medium to long term."
'The real heroes'
He added: "Get Afghanistan and anything else immediately like it right, fully funded, and then we can make sure we make proper provision, as we can afford, for the medium to long term."
Meanwhile, Mr Cameron, who spent the night in Camp Bastion, said the troops could go home with "heads held high" once Afghans could manage their own security.
And he delivered a message from the England football team, who said the troops were "the real heroes".
"It's important you know how much all your effort means to the England players," the message said.
Earlier, soldiers had sent their own good luck video to the players ahead of the start of the World Cup.
Before heading to Camp Bastion on Thursday Mr Cameron was forced to cancel a planned trip to another military base because of a security alert.
Earlier in the day, he announced an extra £67m to tackle the threat of roadside bombs and said the conflict was his "number one priority".
He said nobody wanted troops to be in Afghanistan "a moment longer than is necessary" - a sentiment he repeated on Friday morning to the ranks of soldiers gathered in the desert for his speech.
The PM said he wanted to give troops "proper support" by doubling their operational allowance, which currently stands at £2,380 for a six-month tour.
The increase will come into force from next month and be backdated to the date of the general election on 6 May.
"I want you to help me create a new atmosphere in our country, an atmosphere in which we back and revere and support our military," he added.
On Thursday, Mr Cameron spoke alongside Afghan President Hamid Karzai at his presidential palace in Kabul.
The PM said 2010 was "the vital year" to make progress in stabilising the country.