Lawyers representing the family of the two San Bernardino attackers have said relatives are "in complete shock" over the shooting.

They said the family had no idea Syed Rizwan Farook and his wife, Tashfeen Malik, were capable of such an attack.

The lawyers warned against jumping to conclusions after the FBI said earlier the attack was being investigated as an "act of terrorism".

Wednesday's mass shooting left 14 people dead and 21 injured.

Tashfeen Malik, 27, and her husband Syed Rizwan Farook, 28, died in a shootout with police after the killings in the southern Californian city, east of Los Angeles.

Lawyers David Chesley and Mohamed Abuershaid said there was no evidence that the couple had extremist views or were members of a militant group.

Syed Rizwan Farook's sister, Saira Khan, told CBS News: "I can never imagine my brother or my sister-in-law doing something like this, especially because they were happily married, they had a beautiful six-month-old daughter,"

Farook is said to have been an isolated individual with few friends and Malik has been described by family as a "caring, soft-spoken" housewife.

Chesley said Malik was very conservative. She did not drive or interact with male family members and wore a burka, he said.

The family was aware that Farook owned two handguns and said co-workers had recently made fun of his beard, the attorneys said.

Front-page editorial

In response to the shooting, the New York Times newspaper ran an editorial calling for stricter gun controls on the front page of Saturday's print paper.

It is the first time since 1920 that the paper has run an editorial on page one.

"It is a moral outrage and national disgrace that civilians can legally purchase weapons designed to kill people with brutal speed and efficiency," the opinion piece said.

"America's elected leaders offer prayers for gun victims and then, callously and without fear of consequence, reject the most basic restrictions on weapons of mass killing," it added.

The paper's publisher Arthur Sulzberger Jr said the aim was "to deliver a strong and visible statement of frustration and anguish about our country's inability to come to terms with the scourge of guns".

(BBC)