Image copyright AP Image caption Ashley Guindon had been responding to a domestic incident when she was shot

A US police officer has been shot and killed on her first day at work, the day after she was sworn in.

Ashley Guindon had been responding to a domestic dispute in Woodbridge, Virginia, about 32 km (20 miles) south of Washington, DC.

Two of her colleagues were also injured in the shooting and are in hospital, but no details have been released about their condition.

The suspect, an Army staff sergeant assigned to the Pentagon, was arrested.

Ronald Hamilton, 32, is being held without bail on charges that include murder of a law enforcement officer and first-degree murder, AP news agency reported.

He killed his wife then opened fire on officers as they approached, authorities said.

An unharmed 11 year-old child, reportedly the couple's son, was also in the house at the time of the incident, they added.

Guindon, 28, had been a former Marine Corps reservist and resigned during officer field training for personal reasons last year. Saturday, though, was her first day back on shift in her new role.

Image copyright Prince William County Police Image caption Prince William County Police tweeted this on Friday after Guindon's swearing in

Image copyright AP Image caption On Sunday, dozens of police cars paid tribute to Guindon outside the hospital where her body was held

"It is with profound sadness that we announce that Prince William County Police Officer Ashley Guindon, one of the officers involved in this evening's shooting on Lashmere Ct, has died as a result of her injuries sustained during the incident," her department said in a statement on Saturday.

Prince William County Police had earlier tweeted a picture of Guindon following her inauguration on Friday, urging her and another new colleague to "be safe".