The U.S. Justice Department said one person is now in custody in connection with the mailing of suspected explosive devices that targeted high-profile Democrats including Barack Obama and Hillary Clinton.

The Justice Department plans a news conference Friday at 2:30 p.m., spokeswoman Sarah Isgur Flores said on Twitter.

A dozen packages containing the devices have been intercepted by authorities so far. The intended recipients have all been targets of conservative vitriol, with the most recent packages discovered addressed to New Jersey Democratic Senator Cory Booker and former Director of National Intelligence James Clapper. The first device was found Monday after being delivered to the home of billionaire financier George Soros.

President Donald Trump was briefed on the developments Friday by Chief of Staff John Kelly and law enforcement officials, according to a White House spokesman.

After initially calling for national unity this week as the suspected mail bombs were discovered, Trump began blaming the media for fostering divisiveness in the country. On Friday, he singled out CNN -- which also was targeted by the suspected mail bombs.

“Funny how lowly rated CNN, and others, can criticize me at will, even blaming me for the current spate of Bombs and ridiculously comparing this to September 11th and the Oklahoma City bombing, yet when I criticize them they go wild and scream, “it’s just not Presidential!,” Trump said on Twitter.