President Donald Trump called for unity and denounced political violence Wednesday as federal law enforcement officials investigated a series of apparently explosive packages mailed to Democratic politicians and the cable network CNN.

“In these times, we have to unify. We have to come together,” Trump said in the East Room of the White House before making an afternoon speech about opioid abuse. “Acts and threats of political violence have no place in the United States of America.”

Federal officials said small explosive devices were sent to former President Barack Obama and to former President Bill Clinton and his wife, former Secretary of State Hillary Clinton.

Someone also sent such a package to CNN’s New York office, to Obama’s former attorney general, Eric Holder, and to Rep. Debbie Wasserman Schultz of Florida, former chairman of the Democratic National Committee.

During a press briefing, New York Gov. Andrew Cuomo, a Democrat, said a suspicious package also was mailed to his office.

“The safety of the American people is my highest and absolute priority,” Trump said. “The full weight of our government is being deployed. We will spare no resources and expense.”

First lady Melania Trump spoke before the president on the matter.

“We cannot tolerate those cowardly attacks, and I strongly condemn all who choose violence,” the first lady said.

The spate of suspicious packages sent to Democrats follow weeks during which political activists harassed and yelled at  Republican lawmakers and officials in public places.

Trump was briefed earlier in the day on the situation by White House chief of staff John Kelly; Attorney General Jeff Sessions and his own chief of staff, Matthew Whitaker; White House homeland security adviser Doug Fears; Homeland Security Secretary Kirstjen Nielsen; FBI Director Christopher Wray; Secret Service Director Randolph D. “Tex” Alles; and deputy national security adviser Mira Ricardel.

“This egregious conduct is abhorrent to everything we hold dear and sacred as Americans,” Trump said. “We are extremely, angry, upset, unhappy about what we witnessed this morning. And we will get to the bottom of it.”