Arizona's Republican governor Jan Brewer has been left red-faced -- again -- after mistakenly endorsing President Barack Obama in a live television interview.

The hardline Republican, who famously suffered a televised "brain freeze" in 2010 -- and had a public stand-up row with Obama when he visited Arizona this year -- made the gaffe Wednesday night.

President Barack Obama reinforced his image as the social media president Wednesday as he took questions from the public in an online chat on the Reddit website.

As Republicans gathered for the nominating convention in Florida, Obama chatted about hurricane relief efforts, the space program and Internet freedom in a wide-ranging discussion.

U.S. President Barack Obama said Wednesday he would soon unveil the coveted secret recipe for the White House's storied microbrewed beer after an Internet campaign.

An internet user asked Obama, who participated in a question and answer session over social media network Reddit, for the recipe.

U.S. President Barack Obama on Tuesday declared a state of emergency in a second state, Mississippi, to cope with the expected impact of Hurricane Isaac.

The move followed a similar declaration for Louisiana issued on Tuesday and came as parts of Mississippi and neighboring states were placed under hurricane and tropical storm warnings.

A strengthening Tropical Storm Isaac barreled toward Florida and was predicted to become a hurricane on Sunday, forcing a one-day delay to the main events of the Republican convention, after leaving four people dead in Haiti.

With winds reaching 65 miles (100 kilometers) per hour, the storm left Haiti and swept across Cuba late Saturday, with the Miami-based U.S. National Hurricane Center reporting it would probably reach Florida later in the day.

Republican White House hopeful Mitt Romney on Friday appeared to wade into the birther conspiracy about President Barack Obama when he made a joke about his own birth certificate.

Speaking about his Michigan roots, Romney mentioned the hospitals in which he and his wife Ann were born, then said: "no one's ever asked to see my birth certificate. They know that this is the place that we were born and raised."

An armed man who allegedly made a death threat against U.S. President Barack Obama in an expletive-filled email was charged Wednesday over the incident, court papers showed.

Anton Calouri, 31, is accused of threatening to kill the president and of assaulting a law enforcement official at the time of his arrest Tuesday in Federal Way, a suburb of Seattle, Washington.

British Prime Minister David Cameron and U.S. President Barack Obama warned Wednesday they would be forced to consider a new course of action if Syria threatens to use chemical weapons on rebel fighters.

The two leaders agreed during a telephone call that "the use -- or threat -- of chemical weapons was completely unacceptable and would force them to revisit their approach so far," Cameron's Downing Street office said.

A little more than two weeks after its arrival on Mars, NASA's Curiosity rover will on Wednesday make its first "test drive" before setting off on its Red Planet mission, the U.S. space agency said.

The $2.5 billion rover, which landed on Mars on August 6, has performed a battery of tests and appears ready to embark on its two-year mission to explore the Red Planet in the hunt for signs of life, NASA said Tuesday.

An armed man was arrested in the western United States on Tuesday for allegedly sending an email that threatened President Barack Obama, a justice official told Agence France Presse.

"He had sent an emailed threat against the president," said Emily Langlie, a spokeswoman for the U.S. Attorney's Office in Washington state, confirming that the man was detained at a suburban apartment in Seattle.