US President Barack Obama declared "enough is enough" and made an impassioned call for tighter controls on military-style weapons on Saturday, a day after a gunman killed three people at a family planning centre.
Details began to emerge about what may have possibly driven the suspected shooter, Robert Lewis Dear, 57, to hold a more than five-hour siege of a Planned Parenthood clinic in Colorado Springs on Friday that left a policeman among the dead and nine others wounded.
"Eyewitnesses confirm that the man who will be charged with the tragic and senseless shooting... was motivated by opposition to safe and legal abortion," said Vicki Cowart, president and CEO of Planned Parenthood Rocky Mountains.
"This is an appalling act of violence targeting access to health care and terrorising skilled and dedicated health care professionals."
The clinic performs abortions - a highly emotive and divisive issue in America.
Dear eventually surrendered and is in police custody, after just the latest deadly rampage to convulse the United States.
Police said a total of 24 people who had at one point been in a hostage situation were evacuated unharmed from the Planned Parenthood building, while some 300 people hunkered down in surrounding businesses.
Obama said the suspect was armed with an assault weapon and had held hostages at the Planned Parenthood centre, from which he opened fire at people outside.
"This is not normal. We can't let it become normal," a clearly frustrated Obama said in a statement.
"If we truly care about this - if we're going to offer up our thoughts and prayers again, for God knows how many times, with a truly clean conscience - then we have to do something about the easy accessibility of weapons of war on our streets to people who have no business wielding them.
"Enough is enough."
Planned Parenthood - a major provider of women's health services that receives funding from the government - offers preventive checkups, contraceptives and abortions.
It has 700 clinics around the United States and has been violently targeted before.
"We've seen an alarming increase in hateful rhetoric and smear campaigns against abortion providers and patients over the last few months. That environment breeds acts of violence," said Cowart.
"We do not accept this environment as normal. We should not have to live in a world where accessing health care includes safe rooms and bullet proof glass."
Community in mourning
The gunman entered the Planned Parenthood building before noon on Friday and started shooting from a window. Police surrounded the building, and after an exchange of gunfire and a standoff stretching into the evening, the gunman surrendered.
Several people had managed to flee the building, running out in tears into the freezing outdoors, while others made it into the sanctuary of a safe room in the clinic.
Police and officials were giving little away about Dear, whose police booking photos showed him sporting a bushy gray beard.
But US media described him as a seemingly troubled loner with several minor run-ins with the law.
The Colorado Springs Gazette said he had arrest records in South and North Carolina on misdemeanor charges and said he also faced peeping tom charges in 2002 in South Carolina, but the charges were dismissed.
Mayor John Suthers, who along with police and other officials watched the drama unfold on the clinic's security cameras, paid tribute to police for hauling in the gunman without further bloodshed.
The wounded included five police, but none of the injured were seriously hurt.
"We are in mourning today," Suthers told a news conference, saying that police, particularly SWAT teams were "responsible for saving many many lives yesterday."
The dead policeman was identified as Garrett Swasey, 44, a campus officer at the University of Colorado at Colorado Springs who had raced to the scene of the shooting.
Officials expect to name the two other dead on Monday.
Colorado Springs, which is traditionally a conservative bastion in Colorado, was "immersed in sorrow and grieving," said Governor John Hickenlooper.
Local media said that extra police were sent to protect the three other Planned Parenthood clinics in the Denver area.
The organisation was the focus of intense media interest earlier this year when anti-abortion activist David Daleiden spent more than two years secretly filming meetings with Planned Parenthood officials.
He had passed himself off as an intermediary that works with abortion clinics and research facilities.
He says the videos show Planned Parenthood officials discussing the sale of foetal tissue and changing rules to leave certain organs of an aborted fetus intact. The organisation says the videos were doctored.
Nevertheless, Planned Parenthood has become a lightning rod for criticism by social conservatives.