There's developing news in Boston. This comes from the Associated Press:

A man has been arrested on federal terrorism-related charges in Massachusetts.

A person familiar with the investigation who spoke on condition of anonymity says the man was arrested early Wednesday. The person was not authorized to divulge details of the investigation.

The man has not been identified publicly, and the U.S. attorney's office plans to release more details at a news conference Wednesday morning.

The Boston Globe reports that "federal authorities say they have foiled plots to launch terrorist attacks inside and outside the United States with the arrest this morning of a 27-year-old man in Sudbury. According to a federal official, one man is in custody and two others have been implicated in the plots."

That news conference is scheduled for 10 a.m. ET.

Update at 10:22 a.m. ET. The AP adds that:

Authorities in Boston say Mehanna sought training in terrorist training camps and worked with others from 2001 to May 2008 on the conspiracy to "kill, kidnap, maim or injure" people in foreign countries and to kill prominent U.S. politicians.

Federal prosecutors say Mehanna and his conspirators tried to get automatic weapons for a mall attack, but their plans were foiled when they could not get the weapons.

Mehanna's attorney, J.W. Carney Jr., did not immediately return calls for comment.

Update at 10:10 a.m. ET: At the briefing, U.S. Attorney Michael Loucks just alleged that Tariq Mehanna, 27, and his co-conspirators discussed attacking civilians at a shopping mall with automatic weapons.

Reuters says that:

Mehanna had been previously indicted in January 2009 for making false statements to the Federal Bureau of Investigation and other officials in connection with a terrorism investigation, the U.S. Justice Department said in a news release on Wednesday.

Update at 10:05 a.m. ET. The Associated Press now reports that:

A Massachusetts man has been arrested on federal terrorism-related charges on suspicion of planning attacks inside and outside the United States. A person familiar with the investigation who spoke on condition of anonymity says the man was arrested early Wednesday. The person was not authorized to divulge details of the investigation. The person says the man is from the Boston suburb of Sudbury and had two co-conspirators.