Top Obama administration officials asked senators Thursday not to set benchmarks for measuring progress in Afghanistan and Pakistan when they draft a supplemental spending measure next month.

Some lawmakers want the $83.4 billion bill, which would fund military operations in Iraq and Afghanistan for the rest of this fiscal year, to include benchmarks to measure the success of President Obama’s new approach that treats Afghanistan and Pakistan as a single issue.

But Defense Secretary Robert M. Gates and Secretary of State Hillary Rodham Clinton told the Senate Appropriations Committee that would be a bad idea. The administration is working on a list of benchmarks to cover political, economic, and security issues, they said, but admitted that not all would likely be made public.

“I hope that Congress will give us a chance to put these in place,” Clinton said, adding, “I think it will be a better approach if we can do this in the context of the departments and not legislatively mandated at this point.”

While the yardsticks would be shared with lawmakers, “We haven’t made a final decision whether they can be made in some form public,” Clinton said.

The supplemental — the second such measure for fiscal 2009 — would be the first opportunity for lawmakers to weigh in on Obama’s approach.

Making the benchmarks widely available “would help build public support,” said Sen. Ben. Nelson, D-Neb., a longtime advocate of legislatively mandated benchmarks.

“We’ll make public as much as we can,” Gates replied, noting that some measures would need to be classified for security reasons.

The administration is seeking $75.5 billion to fund military operations in Iraq and Afghanistan through Sept. 30 and about $7 billion for the State Department and related civilian operations.

The first supplemental appropriated $65.9 billion last year for those purposes.

The House Appropriations Committee, meanwhile, will mark up its version of the funding bill May 7.