As the Bush administration presses for tougher sanctions against Iran, Congress is unlikely to take its own punitive measures this fall.

Two House-passed bills — one that would tighten sanctions ( HR 957 ) and one that would encourage divestment from companies that do business in Iran ( HR 2347 ) — are likely to stall in the Senate because of procedural roadblocks, a crowded legislative calendar and opposition from the Bush administration, which doesn’t want Congress tying its hands on foreign policy.

A third bill is likely to pass the House later this month, but its companion measure in the Senate lacks the support of key lawmakers.

Senior administration officials announced Wednesday that they are planning to meet in Washington next week with representatives of Germany and the other permanent members of the U.N. Security Council — France, Britain, Russia and China — to discuss new U.N. sanctions to persuade Iran to halt its nuclear program, which is suspected of developing nuclear weapons.

Iran says the program is being used for peaceful purposes only.

The United Nations already has imposed two sets of mild sanctions on Iran, but Tehran claims to be building centrifuges to enrich uranium at a record pace.

On Capitol Hill, a group led by Sen. Richard C. Shelby of Alabama has placed holds on the two House bills. Shelby, the ranking Republican on the Banking, Housing and Urban Affairs Committee, said he supports tightening the noose around Iran but wants to go through the hearing and markup process.

Shelby has asked Banking Chairman Christopher J. Dodd , a Democrat who represents Connecticut and a presidential candidate, to hold a hearing on the bills. Dodd is open to the idea, though the panel held a similar hearing in March.

Meanwhile, the Bush administration opposes the legislation in principle because the measures would complicate the president’s conduct of foreign policy. The divestment bill, for example, would punish other countries, such as Russia, China and France, for doing business with Iran.

“Increasing unilateral American sanctions targeted at United States allies and diplomatic partners would shift focus away from Iran’s unacceptable behavior, onto differences between the U.S. and its partners, and would impair the administration’s ability to employ effective multilateral approaches, including multilateral sanctions,” Assistant Secretary of State Jeffrey Bergner wrote in a July letter to Barney Frank , D-Mass., the chairman of the House Financial Services Committee, who sponsored the divestment bill.

Some Democrats also want to avoid provoking Iranian President Mahmoud Ahmadinejad into resisting international efforts to curtail Iran’s nuclear program.

Gary Sick, an Iran scholar at Columbia University’s School of International and Public Affairs, also said Congress risks undermining international efforts. “If you are trying to hold a coalition together on the Security Council, coming down unilaterally on their companies is not the way to do it,” Sick said.

Later this month, the House is likely to pass a catchall anti-Iran measure ( HR 1400 ), sponsored by Foreign Affairs Chairman Tom Lantos , D-Calif. That bill had been bogged down by referrals to five committees, but they must all discharge it by Sept. 21.

Although the bill has 324 cosponsors, a strong vote in the House may be the last word. The bill’s Senate companion ( S 970 ) has 69 cosponsors, but notably absent are key players such as Majority Leader Harry Reid , D-Nev., and Foreign Relations Chairman Joseph R. Biden Jr. , D-Del.

Gordon H. Smith , R-Ore., who sponsored the Senate’s Iran package, may try to offer it next week as an amendment to the defense authorization bill ( HR 1585 ).

“I am trying to look for the right timing to be helpful, but the Europeans can’t have it both ways,” Smith said Wednesday. “They can’t just continue business as usual with Iran and then be surprised that we’re at the brink of military conflict.”

Meanwhile, the Senate version of the divestment bill ( S 1430 ), sponsored by Barack Obama , D-Ill., has been referred to the Banking panel. Dodd is working with the Treasury Department to address the administration’s objections to the measure.

Iran’s critics, however, say the United States should push against Tehran in every venue it has, including Congress.

“It is so pitiful to see a president huff and puff when he is so unwilling to inconvenience a multinational corporation,” said Brad Sherman , D-Calif., chairman of the House Foreign Affairs Subcommittee on Terrorism, Nonproliferation and Trade.

Mark Steven Kirk , R-Ill., who co-chairs a House working group on Iran, said a hard line from Congress could help the administration in its international campaign to rein in Iran’s nuclear program.

“My read on the administration overall is that Congress playing bad cop is a very valuable tool,” Kirk said.