An Air France flight from San Francisco to Paris was diverted to Montreal "as a precaution" after an "anonymous threat," the airline told AFP on Tuesday.

Flight AF083 from San Francisco to the main Paris airport of Charles de Gaulle touched down just before midnight local time in Montreal, the firm said.

More than 1,500 homes have been destroyed in two immense fires that have torn through California over the last week, causing millions of dollars in damage, state officials said Monday.

The Valley and Butte fires, about 100 miles (160 kilometers) from San Francisco, will cost "in the tens of millions, if not in the hundreds of millions," Brad Alexander, spokesman for the state's Office of Emergency Services, told AFP.

A 4.0-magnitude earthquake shook the San Francisco area Monday, the U.S. Geological Survey reported, but no major damage or injuries were immediately reported.

Its epicenter was one mile north of Piedmont, about 13 miles (21 kilometers) east of San Francisco on the Hayward Fault.

A businessman with a history of mental illness rushed into a kindergarten and stabbed his ex-partner to death in front of a group of petrified three- and four-year-old children in Argentina on Wednesday.

Police had issued a restraining order against the man and given the woman a panic button, but the measures failed to prevent him stabbing his 44-year-old ex-partner in the neck repeatedly with a knife.

U.S. authorities have launched a nationwide manhunt for a 42-year-old man who went on the run after explosives were found at his home in San Francisco, they said Monday.

Ryan Kelly Chamberlain II, 42, was last seen Sunday driving a car south of San Francisco with either California or Texas license plates.

A powerful 6.9-magnitude earthquake struck late Sunday off the coast of northern California, the U.S. Geological Survey said, but there were no immediate reports of damage or a tsunami threat.

The quake struck at 0518 GMT with an epicenter located 77 kilometers (48 miles) west-northwest of the town of Ferndale and at a depth of seven kilometers (4.3 miles), said the USGS, which monitors earthquakes worldwide.

U.S. investigators have arrested a Chinese-born man over an arson attack on China's consulate in San Francisco which triggered strong protest from Beijing, officials and reports said Monday.

Yan Feng, 39, who lives south of the city, surrendered to police on Friday and has been charged with criminal offenses including causing damage to a diplomatic mission, said the Federal Bureau of Investigation.

The wildfire threatening Yosemite National Park grew Tuesday to become California's seventh biggest ever, as firefighters battled to protect San Francisco's main water supply.

The so-called Rim Fire now covers some 180,000 acres (73,000 hectares) -- an area bigger than Chicago -- and was still only 20 percent contained, albeit up from 15 percent on Monday.

A wildfire raging on the edge of the Yosemite National Park on Monday threatened both one of America's premier sites of natural beauty and a reservoir that supplies San Francisco.

The massive blaze, which began nine days ago, has grown to become the 13th largest in California's recorded history, authorities said.

A $60 million research ship funded by a Google executive is setting sail from San Francisco to study a so-called "dead zone" in the Pacific Ocean and other mysteries of the sea.

The San Francisco Chronicle reports the 272-foot (83-meter) vessel called Falkor was scheduled to leave port Thursday.