WASHINGTON (AP) - Increasing the size of the Army, strained by America's two ongoing wars, will cost an estimated $70 billion, a top Army general said Tuesday.

And if yet another conflict were to develop before the force can be bolstered, it would take longer to fight and cost more American casualties than otherwise might be expected, said Lt. Gen. Stephen Speakes, a deputy chief of staff.

Reversing previous administration thinking, President Bush said last month that he wants a larger military. And Defense Secretary Robert Gates earlier this month recommended that the Army's troop strength be increased by 65,000 soldiers, to a total of 547,000 worldwide and the Marines be increased by 27,000 to 202,000. Almost half of that Army increase already has been achieved under a temporary program that Gates said would be made permanent; the full increase is to be achieved within five years.

The Army's preliminary estimate is that it would cost $70 billion to increase its size and the funds would be spread over budget years 2009 through 2013, Speakes told a defense writers group Tuesday .

Army Chief of Staff Gen. Peter Schoomaker has said that the service budget jumps $1.2 billion with each 10,000 soldiers that it recruits and trains. Speakes said the $70 billion figure includes everything - from equipment to pay to health benefits. No figure was immediately available for the increase in the Marine Corps.

"What we are asking is that Americans make a decision about priorities," he said of the huge new defense cost.

Meanwhile, he acknowledged, fighting the war in Iraq on top of the war in Afghanistan has left ground forces in a weakened state of readiness.

That is, some units are below the standard measure used to determine if they are ready to fight a conventional, high-intensity war. This is because they have substantial equipment shortfalls and their training is focusing on the low-intensity, counterinsurgency battle being fought in Iraq.

"What America needs to do is realize that we can fulfill the national strategy (of defending against another conflict simultaneously), but ... that it will take more time and it will also take us increased casualties to do the job," he said.

"We have an issue, and that's part of what, I think, the recent decisions by the president and secretary of defense have addressed," Speakes said. "We're going to build a more robust Army, we're going to continue to invest in a ground force that has the right capabilities, the right equipment, the right training to do it's job," he said, adding that enormous improvements in the quality of the Army have been made in recent years.

"This is a voyage in progress, it's being measured against the harsh litmus test of combat which has forced some grim realities on all of us," Speakes said.