Richards said he backs the government's strategy, but added it was right for him to be "candid" about the effects of reducing military resources and personnel, The Daily Telegraph reported Wednesday.
"It is the job of senior military commanders to help the government assess priorities against the resources available, especially in the current economic conditions," he said. "It is right that candid military analysis keeps the government aware of constraints while the government, rightly, seeks to achieve the maximum effect with the assets available.
Richards voiced his concerns last week during a speech at Oxford University. He said the armed forces' resources and personnel were cut, but operational demands weren't, warning the reduction would negatively affect Britain's world influence.
"We have a whole load of tasks expected of us. Our political masters are quite happy to reduce the size of the armed forces, but their appetite to exercise influence on the world stage is, quite understandably, the same as it has always been," Richards said. "Often politicians say to me, 'Can you go and do this?' I say to them, 'With what?'"
If resources and numbers keep being reduced, eventually "there is going to be a give," he said.
Richards also expressed concerns about the NATO mission in Afghanistan, saying Western leaders "collectively failed" by wasting gains won by years of military operations.
"All the military can do is buy space and time and opportunity for a political resolution of a problem. It is a great shame that we have not understood this," he said last week. "This is not a matter for military, diplomats, politicians. This is a matter of collectively failing to exploit the opportunity the military gained."
Everyone agrees an insurgency can't be won solely by military means, Richards said Tuesday, explaining "it has always been understood that a political solution will ultimately be required."