Hillary Clinton reiterated her call for gun safety reforms, saying this week's murder of Virginia journalists during an on-air broadcast shows that "something is deeply wrong" in America.
At least nine people were murdered in Chicago over the Independence Day weekend in an explosion of gun violence branded "simply unacceptable" by its mayor.
A gun-toting couple possibly linked to anti-government militias killed two US cops execution-style and left a swastika on the bodies, in America's latest chilling shooting rampage, police said.
Police in China have seized a huge cache of weapons including 15,000 guns and 120,000 knives from an illegal arms ring and detained 15 suspects, state media reported.
An internal power struggle within the once-powerful Gulf drug cartel has left 28 people dead in gunfights on Mexico's northeastern coast this week, authorities said.
The death toll from two days of gunfights in Mexico's northern state of Tamaulipas rose to 24 on Monday after authorities reported six more slayings in the drug violence-plagued region.