Obama in gun law plea after Washington Navy Yard deaths
President Barack Obama has renewed calls for changes to US gun laws at a memorial service for the victims of last week's shooting at the Washington Navy Yard.
Mr Obama said tears were "not enough".
The president told mourners Americans must insist that "there is nothing normal about innocent men and women being gunned down where they work".
Twelve people were killed last Monday by contractor Aaron Alexis, who was himself shot dead by police.
The 34-year-old reportedly had untreated mental health difficulties.
Mr Obama called on Americans to abandon their "creeping resignation" to mass shootings.
Acknowledging that "the politics are difficult" - a reference to his failure to get measures through Congress earlier this year - the president said change would not come from Washington.
"Change will come the only way it ever has come, and that's from the American people," Mr Obama told the crowd.
He noted that this was the fifth time he had spoken at a memorial event for victims of a mass shooting since the start of his presidency.
After the massacre at the Sandy Hook elementary school in Connecticut last December, the president sought to introduce expanded background checks for buyers of guns, and to re-introduce an expired ban on military-style assault weapons.
Those measures have effectively died in the Senate, as they will not get the 60 votes needed to pass.
United Nations statistics show the US has a much higher rate of firearm-related murder than other developed nations.
'Not just statistics'
Mr Obama and his wife Michelle met privately with victims' relatives ahead of the shooting memorial, the White House said.
The BBC's correspondent in Washington, Katy Watson, reports that as well as using the speech to address the issue of gun crime, the president talked in detail about the victims' lives and families.
He wanted to make sure these people were remembered for who they were, not just gun crime statistics, our correspondent says.