Sept. 26 (Bloomberg) -- President Barack Obama said he remains open to “a serious, meaningful dialogue” with Iran after the U.S., France and Britain disclosed the Islamic Republic has been building a secret nuclear-fuel facility.

Iran first must “cooperate fully” with international arms inspectors and “take actions to demonstrate its peaceful intentions,” the president said in his weekly radio and Internet address.

Obama, keeping up pressure on Tehran, said the underground nuclear facility poses “a serious challenge to the global nonproliferation regime, and continues a disturbing pattern of Iranian evasion.”

The president along with French President Nicolas Sarkozy and U.K. Prime Minister Gordon Brown disclosed its existence yesterday morning at the Group of 20 nations summit in Pittsburgh. They demanded Iran submit to international demands that it halt uranium enrichment and fully open its nuclear program to inspectors.

Iranian President Mahmoud Ahmadinejad yesterday disputed the accusation and called the site “a very ordinary facility in the beginning stages.”

The disclosure precedes talks Oct. 1 in Geneva, when the U.S., Britain, France, China and Russia -- the five permanent United Nations Security Council members -- and Germany will sit for negotiations with Iran to limit its nuclear program.

New Urgency

Those talks “now take on added urgency,” Obama said.

The president said Iran “must pursue a new course or face consequences.” Without specifying what sanctions Iran might encounter, Obama said the government in Tehran “will face increased pressure and isolation, and deny opportunity to their own people.”

Obama stood by his past offers to negotiate.

“My offer of a serious, meaningful dialogue to resolve this issue remains open,” he said.

Obama devoted most of his remarks to what he called “real progress” in advancing U.S. and global economic prosperity at the Pittsburgh summit.

That included, he said, an agreement by the participants to phase out $300 billion worth of fossil fuel subsidies, which he said would increase energy security and reduce greenhouse gas emissions.

Republican Address

In the Republican address, Senator Johnny Isakson of Georgia criticized Obama’s health-care agenda, saying the president and congressional Democrats are rushing to pass “a massive overhaul that will raise their taxes, lower their quality of care and put government between them and their doctor.”

Isakson said the proposal being worked on by the Senate Finance Committee would “cut Medicare for our seniors” while “dramatically” expanding Medicaid, the health-care program for the indigent jointly financed by the federal and state governments.

Isakson described the Republican prescription as “strengthening the doctor-patient relationship by using choice and competition, rather than rationing and restrictions, to contain costs and ensure access to affordable health care.”

Republicans also favor greater emphasis on wellness and disease management, as well as “common-sense” measures to eliminate frivolous lawsuits against doctors and hospitals, he said.

The finance committee, led by Max Baucus, a Montana Democrat, is set to resume debating the proposal Sept. 29.

To contact the reporter on this story: Edwin Chen in Washington at Echen32@bloomberg.net

Last Updated: September 26, 2009 06:00 EDT