President Barack Obama and his wife, Michelle, walk with their daughters, Sasha and Malia, right, from the White House to a Sunday service Dec. 11, 2011, at nearby St. John's Church. (Manuel Balce Ceneta/AP)

A news story that the White House sought to suppress became a news story anyway on Tuesday in an episode that underscores the difficulties of maintaining the privacy and security of President Obama’s underage daughters in a digital world.

White House officials on Monday urged Web sites to take down a wire service report about a spring-break trip to Mexico by one of the president’s daughters. The story, officials said, violated an unwritten rule guiding news coverage of the president’s family — that is, that the media don’t report on routine or mundane activities involving Obama’s children.

“From the beginning of the administration, the White House has asked news outlets not to report on or photograph the Obama children when they are not with their parents and there is no vital news interest,” said Kristina Schake, the spokeswoman for first lady Michelle Obama in a statement early Tuesday. “We have reminded outlets of this request in order to protect the privacy and security of these girls.”

But the administration decided to acknowledge the trip after an earthquake measuring 7.4 on the Richter scale struck Mexico on Tuesday, potentially imperiling Malia Obama, 13, and her friends. That spurred questions from reporters about Malia’s safety, compelling the administration to issue a statement that she was in Mexico and safe.

Presidential administrations have long been protective of the first family’s minor children, and reporters in Washington have mostly observed the taboo on stories or photographs of them outside official and semi-official events. The ban on such coverage has existed through many administrations by informal agreement with the White House Correspondents’ Association, which represents the interests of journalists who cover the president.

“There’s a general feeling among the press corps that it wants to be respectful” of the president’s children, said Caren Bohan, the White House reporter for Reuters who is president of the WHCA. “I’m a parent of two school-age children myself, so I completely understand that their parents want privacy for them. I think a lot of reporters respect that.”

While traditional news organizations have long abided by such arrangements, the Mexico incident demonstrates how difficult it is to enforce such standards in an age of “globalized news,” said Martha Joynt Kumar, a political science professor at Towson University who studies the media and the presidency.

The report about the spring-break trip emanated not from Washington but from a reporter for Agence France-Presse based in Mexico. The story, citing an anonymous state police official in Mexico, reported on details of the visit. It was picked up by a number of Web sites, including the Huffington Post, Britain’s Daily Telegraph, the Ottawa Citizen and Montreal Gazette in Canada, and the Australian.

White House officials persuaded several of the sites to remove the article, but reports about the scrubbing effort soon called attention to the original story’s existence elsewhere on the Internet.

“The problem with the Internet is that everyone sees themselves as a newsmaker,” Kumar said. That makes it difficult for traditional news outlets to maintain a de facto ban on reporting a piece of news, she said. “You’re dealing with a different universe now. Everyone has an iPhone and takes pictures. Everyone has [access to social media]. . . . The conditions have changed, and it’s much harder to control information.”

White House officials acknowledge that news organizations can’t exercise the same level of discretion when the president’s daughters are with him, because he’s a public figure. But they are nevertheless protective in public settings. When Obama was greeted by one of his daughters upon his return to the White House after a trip in June 2009, for example, press officers asked photographers not to distribute the shot to protect her privacy. Most complied with the request.

One potential exception to the usual rule: news of wrongdoing involving a president’s child. The media widely reported in 2001 that Jenna and Barbara Bush, the daughters of President George W. Bush, were both cited for underage drinking in Austin.

Some journalists suggest that a double standard often is at play. Presidents, and presidential candidates, frequently are photographed with their children and deploy them to score political points. Then-candidate Bill Clinton and wife Hillary Rodham Clinton, for example, posed for a People magazine cover photograph with their 12-year-old daughter, Chelsea, in July 1992 — a sunny image of a nuclear family that may have helped voters put aside concerns about accusations of the candidate’s philandering past.

Obama has said he is reluctant to draw his children into a political context. But he has occasionally done so, such as early this month when he told Sandra Fluke, the Georgetown law student insulted by Rush Limbaugh over her advocacy of mandated insurance coverage for contraception, that he wouldn’t want his daughters spoken about as Limbaugh had about Fluke. The White House also has permitted photographers to take pictures of the girls while they were on vacation with their parents, and it has issued its own photos of them accompanying their parents.

The Washington Post reported last month that the president’s reelection campaign features a portrait of the first family asking supporters to “help the Obamas stand up for working Americans.” The story quoted Democratic pollster Celinda Lake on the political appeal of Obama’s family: “The value of the family is enormous. The more you know this family and the more you think of Barack Obama in these terms, the harder it is to vilify him.”