(CNN) -- Military operations will need to be reduced for the rest of the year unless Congress approves additional funding for the wars in Iraq and Afghanistan, Defense Secretary Robert Gates warned senators Wednesday.
"I am becoming increasingly concerned about the lack of progress on the supplemental and strongly urge Congress to complete its work on the request as quickly as possible," Gates told the Senate Appropriations Committee.
The Pentagon has requested an additional $33 billion to support the added financial costs of President Barack Obama's new strategy for the war in Afghanistan, now the longest conflict in U.S. history. Gates told senators that if there is no passage of the funding by the July 4 congressional recess, "We will have to begin planning to curtail defense operations."
"Such planning is disruptive, can be costly and especially in a time of war, and I ask your help in avoiding this action," he said.
Gates also reiterated his promise to urge Obama to veto the 2011 defense budget if lawmakers keep programs he considers a waste of money, such as additional C-17 cargo planes or an alternate engine design for the F-35 Joint Strike Fighter.
"Let me be explicit: It would be a very serious mistake to believe the president would accept these unneeded programs simply because the authorization or the appropriations legislation includes other provisions important to him and this administration," the secretary said.
Last month, Gates began a hard-line program to reform the Pentagon's overhead costs and to find a goal of saving $100 billion over the next five years to put back into personnel, military units and future capabilities.
Senators also used the budget hearing to question Gates about Afghanistan, and he used the platform to tell the panel that there is progress happening among all the news of 27 troops killed since the start of June.
"I think, frankly, that the narrative over the last week or so, possibly because of the higher casualties and other factors, has been too negative," Gates said.
"I think that we are regaining the initiative. I think that we are making headway," he continued.
And when asked what he thought of the controversial Afghan President Hamid Karzai, gone was any negative tone the administration had used weeks ago.
"I think that he is embracing his responsibility for this conflict," Gates said.
Senators continued to press on the increasing number of troop deaths, and questioned the success in the Marjah operation, the military's first big push against the Taliban under the new Obama strategy.
While Gates responded tersely that the administration had said there would be an increase in deaths as more troops went into the country, Joint Chiefs Chairman Adm. Mike Mullen, who was testifying alongside Gates, warned senators about repeated questions during monthly hearings.
Mullen said progress in Marjah, in southern Afghanistan, is "slow and steady," but Taliban fighters "are still there and are intimidating."
"I would not, though, ask routinely when we will be be successful in Marjah," he said, adding, "I think we will know by the end of the year where we are with respect to reversing the momentum."
But he did say he was concerned about people pinning their hopes on the stated July 2011 date when troops are slated to start leaving Afghanistan.
"We are just not going to know until we get much closer to July 2010 how many troops and where they will come from ... and all of that is conditions-based," Mullen said. "And we have not gotten to July 2010 yet."
And Gates added, "I think the war in Afghanistan will end much like the war in Iraq had ended ... as we did it province by province in Iraq, I suspect that's how it will happen in Afghanistan." He quickly clarified, "I'd caution to say the Iraq war is ending, not 'has ended.' "