Administration experts on Iraqi reconstruction frustrated Senate Foreign Relations Committee (search) members Wednesday when they were unable to provide information on costs and other details of the undertaking.

"My constituents want to know how much we are going to pay," said Sen. Russ Feingold, D-Wis., clearly disappointed by the responses of four administration witnesses at a committee hearing.

Sen. Chuck Hagel, R-Neb., said it was a "little puzzling" that Undersecretary of Defense Dov Zakheim (search) did not know the number of British troops left in Iraq.

He then expressed incredulity when Zakheim said the number of U.S. troops deployed in Iraq was classified.

"You're kidding," said Hagel, noting that news reporters seemed to have no difficulty in coming up with the figure. The most widely quoted number is 160,000 U.S. troops.

Sen. Joseph Biden, D-Del., the ranking Democrat on the committee, showed impatience when Zakheim failed to provide an estimate on the expected cost of the U.S. troop deployment in Iraq for the next fiscal year.

"I can't do it. I can't look to the future," Zakheim said.

Biden replied, "If you don't have any idea for 2004, it's not the same DoD (Department of Defense) that I remember."

If the Pentagon is simply going to wait before providing the information, "then I would regard that as irresponsible," Biden added.

Zakheim said: "It takes time. It's not a matter of waiting."

Several senators expressed interest in a cabinet-level conference expected to be held in September at which donor countries will pledge assistance for Iraq.

Sen. Paul Sarbanes, D-Md., wondered why the United States could not suggest percentages to each donor country.

"If we lay out percentages, we run the risk of scaring people off," Zakheim said. U.S. officials would be asked, "Who are you to fix percentages?" he said.

Other administration witnesses were able to fill in some of the blanks for the committee.

Undersecretary of State Alan Larson, citing private estimates, said Iraqi oil production could increase from its current level of 800,000 barrels per day to 2 million by the end of the year.

And Andrew Natsios, administrator of the Agency for International Development (search), said 440,000 metric tons of food already has been shipped to Iraq with 1 million more scheduled by September.

A resumption of commercial air traffic is on the horizon, he said, adding that the availability of electricity in Baghdad is up to prewar standards.

The process is "accelerating quite rapidly," Natsios said.

Committee chairman Richard Lugar, R-Ind. (search), agreed that "we're getting somewhere."