WASHINGTON (AP) — Hillary Rodham Clinton e-mailed her staff on an iPad as well as a BlackBerry while secretary of state, despite her explanation she exclusively used a personal e-mail address on a homebrew server so that she could carry a single device, according to documents obtained by The Associated Press.

The dispute over her e-mails has cast a shadow over Clinton, the front-runner for the Democratic presidential nomination who is widely expected to announce her candidacy next month.

The State Department released a total of four e-mails between Clinton and her top advisers as part of a Freedom of Information Act request filed in 2013 by the AP, which sought Clinton’s correspondence with senior advisers over a four-year period relating to drone strikes overseas and U.S. surveillance programs.

While limited, the e-mails offer one of the first looks into Clinton’s correspondence while secretary of state. The messages came from and were sent to her private e-mail address, hosted on a server at her property in Chappaqua, N.Y., as opposed to a government-run e-mail account.

They show that Clinton, on at least one occasion, accidentally mingled personal and work matters. In reply to a message sent in September 2011 by adviser Huma Abedin to Clinton’s personal e-mail account, which contained an AP story about a drone strike in Pakistan, Clinton mistakenly replied with questions that appear to be about decorations.

The other e-mails between Clinton and her advisers provided by the State Department contained a summary of a 2011 meeting between Sen. John McCain and senior Egyptian officials in Cairo. It was uncensored and did not appear to contain sensitive information. That e-mail was forwarded to Clinton’s private account from Abedin’s government e-mail address.

In another note, Clinton expressed apparent dismay at leaks of classified U.S. government information to the media. Referencing a CNN story, which described “loose lips” in the Obama administration, she asked two officials if she should comment on the matter as had Leon Panetta, the former Central Intelligence Agency director.

“I think this is both dishonorable and dangerous and want to find way to say it,” she wrote.

Clinton spokesman Nick Merrill said early Tuesday that the secretary used her iPad from time to time, primarily to read news clippings.

At the United Nations earlier this month, Clinton said she chose a personal account over a government one out of convenience, describing it as a way to carry a single device, rather than one for work e-mails and another for personal messages.

“Looking back, it would have been probably, you know, smarter to have used two devices,” Clinton said. Her office that day released a statement saying she “wanted the simplicity of using one device.”

Clinton became secretary of state in 2009, a year before Apple Inc. released the iPad. Clinton at that time could have potentially split her accounts, reverting to an official State.gov e-mail account and BlackBerry for work and leaving her personal e-mail on her iPad.

Clinton has said she exchanged about 60,000 e-mails in her four years in the Obama administration, about half of which were work-related. She said none contained classified information, and that her private e-mail system did not suffer any security breaches.

The highly unusual practice of a Cabinet-level official physically running her own e-mail server gave Clinton complete control over access to her message archives.

Clinton said she deleted e-mails — some 30,000 in total — that she described as personal in nature, such as yoga routines, plans for her mother’s funeral or her daughter’s wedding. It’s not clear how Clinton handled e-mails that mixed personal and official business, such as the exchange with Abedin.

Rep. Trey Gowdy, chairman of a House committee investigating the 2012 Benghazi attacks that killed four Americans, said Clinton wiped her e-mail server “clean,” permanently deleting all e-mails from it and has declined to relinquish her server to a third party for an independent review.

Clinton’s attorney said she had turned over to the State Department all work-related e-mails sent or received during her tenure and it would make no sense to turn over her server, since “no e-mails … reside on the server or on any backup systems associated with the server.”

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