Moscow's presidential envoy for Syria said Russia "is ready to provide all possible help, including the assistance of the Syrian government forces."
The bomber died and three employees were injured by the blast, which investigators are treating as an act of terrorism.
"He was elected to be president of the United States, not a mental patient," a former Clinton press secretary said.
"The media also has a responsibility to set a civil tone and to stop the endless hostility and constant negative and oftentimes false attacks and stories," Donald Trump said.
The president has used campaign rallies to "constantly stir up hatred against CNN, Hillary Clinton and Barack Obama," Scarborough tweeted.
There has been no information that the series of bomb threats have any link to President Trump.
Explosive devices were sent to Barack Obama, Hillary Clinton and the offices of CNN.
Some of President Donald Trump's far-right conspiracy theorist supporters immediately ridiculed reports of bombs at homes of the Obamas, Clintons and George Soros as "false flag" operations by the Democratic Party.
Broadcaster NOS published an article describing the billionaire as "the Jew Soros" and noting his influence in U.S. politics.
Police told The Associated Press that it was not a "hoax device."
A convicted pedophile sent letters threatening to rape a judge and a probation officer as well as bomb a West Virginia courthouse.
The suspect was planning to detonate a device on the day of the midterm elections.
President Donald Trump mocked the drone attack during a presidential rally in Venezuela, but it could happen in the U.S. as well.
Sunday marks 98 years since a 100-pound bomb turned the iconic street into a scene of bloody chaos.
The 90-year-old said her husband had kept the item on display at home since 1943, but it caused a frenzy when police discovered it was a live explosive.
Two reports, one of which may have been censored by the Israeli military, claim Israel covertly armed and funded Syrian rebels for years.
One man was arrested Tuesday afternoon after an apparent explosive device detonated outside the embassy compound.
A member of the Afghan National Police reportedly shot dead a U.S. soldier in a "green-on-blue" attack.
Russia has said the United States and its Western allies could amass the forces needed to attack Syria in just over a day, claiming they were preparing to do so under the false pretense of a staged chemical attack.
The Russian navy fired off grenades and machine guns in the Mediterranean Sea, where it says the U.S. is preparing to attack Syria under a false pretext.