The Egyptian army helped prevent a civil war during the 2011 uprising, US Secretary of State John Kerry said Thursday, adding American aid to the nation's military had been a good investment.

But he reiterated concerns to US senators about the direction being taken by the new government of President Mohamed Morsi, who was elected Egypt's leader after the toppling of Hosni Mubarak.

"The army in Egypt has been, frankly, an incredibly responsible player in this drama. But for the army, you would have had a civil war, I think, in Egypt. You would have had massive bloodshed," Kerry said.

The Egyptian military, which receives about $1.3 billion in annual aid from the United States, had also "created the capacity to have an election" and then gave up power after Morsi's election last year.

"I think the military has been the best investment that America has made in years in that region," Kerry told the Senate Foreign Relations Committee.

The decades-long ties between the US and Egyptian militaries had paid off during the crisis.

"We had people on the telephone to their military during Tahrir Square saying you've got to be restrained," Kerry said.

"Many of those officers, who were on those tanks or commanding those battalions... responded thoughtfully because they had trained here in the United States, had relationships with people here."

"There was a great deal of communication. And they had a different ethic," he said, adding "they knew they needed to try to be responsible."

The Egyptian army was also now helping to keep peace in the Sinai, and enforce peace in the Gaza Strip.

But Kerry signaled renewed US impatience with the Morsi government, saying there were concerns about "the direction that they appear to be leaning, which is not... that inclusive."

The US administration has promised a further $1 billion in aid, but Kerry only released $190 million during a trip to Cairo in early March.

"Any further aid, we said very clearly, is going to be conditioned on progress on a number of things," Kerry stressed, including economic reforms and restoring "credibility to the political process."

And he voiced apparent regret at the way the 2012 elections turned out, won by the Muslim Brotherhood that "was waiting in the wings, that didn't have much to do with the bringing of the revolution."

"The revolution was young kids looking for a different world and different futures -- a generational revolution, not an Islamic one."