President Obama on Tuesday called Syria a “crumbling” state and acknowledged that the United Nations remains “far from achieving” its goal of returning stability and normalcy to the war-torn nation, but he again ruled out direct U.S. military intervention.

Appearing with French President Francois Hollande at a White House news conference, Obama maintained that international pressure on Syria to account for and relinquish its stockpile of chemical weapons has begun to make progress even as the government of Syrian President Bashar al-Assad has missed a series of deadlines.

“Nobody’s going to deny that there’s enormous frustration here,” Obama said. “Right now we don’t think that there is a military solution per se to the problem. But the situation’s fluid, and we are continuing to explore every possible avenue to solve this problem because it’s not just heartbreaking to see what’s happening to the Syrian people, it’s very dangerous for the region as a whole.”

Obama also defended his administration’s approach to negotiations over Iran’s nuclear program, arguing that the United States will maintain existing economic sanctions while six world powers negotiate a durable nuclear pact with Tehran. But he warned that imposing new sanctions would risk scuttling an interim agreement with Iran, reached in Geneva in November, that freezes key parts of Iran’s nuclear program for six months in exchange for temporary relief on some sanctions.

Obama said he and Hollande agreed that talks in Vienna next week on Iran’s nuclear program “will be an opportunity for Iran to show” that its program is solely for peaceful purposes.

State dinner connoisseur Roxanne Roberts shares some little-known facts about the grand affair. (Jhaan Elker, JulieAnn McKellogg and Jason Aldag/The Washington Post)

“We are absolutely united on our ultimate goal, which is preventing Iran from obtaining a nuclear weapon,” Obama said.

In response to a question, Obama said that “even during this interim agreement, we will fully enforce all applicable sanctions” against Iran. He said French businessmen who have visited Iran recently to explore opportunities should know that “they do so at their own peril right now, because we will come down on them like a ton of bricks” if they violate existing sanctions that the United States controls.

The two presidents met the media after Obama formally welcomed Hollande to the White House on a chilly morning with warm praise for each country’s role in the other’s freedom. Hollande publicly invited Obama to attend the 70th anniversary of the D-Day invasion in June, and Obama announced his acceptance at the joint news conference.

The relationship between the two nations, though strained by recent disclosures that the National Security Agency engaged in large-scale spying on French citizens, has been so tight on foreign policy goals on Syria and Iran that a French reporter asked Obama if the country has surpassed Great Britain as the United States’ top European ally.

“I have two daughters. And they are both gorgeous and wonderful, and I would never choose between them,” Obama said, drawing laughs. “And that’s how I feel about my outstanding European partners. All of them are wonderful in their own ways.”

For his part, Hollande said: “We’re not trying to be anyone’s favorite. There are historic links. We share common values. And I can see that our views converge on many issues. But it’s not about hierarchy; it’s just about being useful to the world.”

During the news conference, Obama also was asked about his administration’s decision Monday to delay the health insurance mandate for medium-sized employers. Under new rules announced Monday by Treasury Department officials, employers with 50 to 99 workers will be given until 2016 — two years longer than originally envisioned under the Affordable Care Act — before they risk a federal penalty for not complying.

Congressional Republicans seized on the announcement as the latest justification for scrapping the health-care law. In particular, they renewed their opposition to the law’s requirement that most Americans have insurance, saying it is unfair to delay rules for businesses and not for individuals.

“This was an example of, administratively, us making sure that we’re smoothing out this transition, giving people the opportunities to get right with the law but recognizing that there are going to be circumstances in which people are trying to do the right thing, and it may take a little bit of time,” Obama said. “Our goal here is not to punish folks. Our goal is to make sure that we’ve got people who can count on the financial security that health insurance provides. And where we’ve got companies that want to do the right thing and are trying to work with us, we want to make sure that we’re working with them as well.”

Hollande was making the first state visit by a French president in nearly 20 years. During a reception on the South Lawn as he arrived at the White House, Hollande told the audience: “Each of our countries knows what it owes to the other — its freedom.” He referred to French aid to the American side during the Revolutionary War and to the U.S. role in liberating France from Nazi occupation in World War II.

Hollande noted that he would be honoring American veterans of World War II during his visit, and he invited Obama to come to France for ceremonies commemorating the June 6, 1944, invasion of Normandy by U.S. and other Allied troops.

Two U.S. veterans of D-Day were in the audience, and Obama led the crowd in paying tribute to them.

“This afternoon, at the Arlington Cemetery, I shall award the Legion d’Honneur, the highest French distinction, to the American Unknown Soldier,” Hollande said. He said he would also present awards to surviving American World War II veterans.

“France will never forget the spirit of sacrifice shown by these American soldiers, nameless heroes who left their homes to liberate my country and Europe,” Hollande said.

After the welcoming ceremony, which featured a military honor guard, Obama and Hollande went into the White House for a series of meetings on such subjects as Iran, Syria and the rise of Islamist extremism in northern Africa.

A highlight of the visit is a state dinner Tuesday evening to be attended by more than 300 guests.

“Few places warm the heart like Paris in the spring,” Obama said in his welcoming speech, as the two leaders joked about the frigid weather. “Today we’re going to do our best with Washington in the winter.”

Obama spoke a few words in French during his speech, observing at the outset that “bonjour” was largely the extent of his knowledge of the language. He said later: “Here, under the red, white and blue — and the blue, white and red — we declare our devotion once more to ‘life, liberty and the pursuit of happiness’ — to ‘liberté, egalité and fraternité.’”

Sitting in the Oval Office afterward without an interpreter, Hollande spoke English with Obama. Accompanying Hollande were French Foreign Minister Laurent Fabius and two main political advisers.

Holland arrived in Washington on Monday, and Obama took him to visit Monticello, the Charlottesville, Va., home of Thomas Jefferson, who was the U.S. envoy to France after the Revolutionary War.

Hollande, 59, is making the state visit without his recently estranged partner, Valérie Trierweiler, following a public breakup over his affair with a French actress, Julie Gayet, 41. Hollande’s romantic travails have captured the attention of the French news media, but the White House has avoided any mention of the drama.