The shooting took place at a subway station in the US capital. Two National Guard soldiers were patrolling there when a man went on the attack, according to police.
Both the soldiers and a suspected perpetrator are being treated in hospital. The soldiers' injuries are described as serious.
Police are describing it as an act of deliberate courage, directed at the soldiers. The incident took place a couple of blocks from the White House.
More soldiers
The man who has been arrested has been identified as a 29-year-old from Afghanistan. He previously served in Afghanistan's US-sponsored army for 10 years, relatives and government sources tell NBC News.
President Trump describes the shooting as a hateful act and an act of terrorism. He is taking several broad measures, including a pause in all immigration cases involving Afghan citizens.
"Now we must reexamine every single foreigner who has entered our country from Afghanistan," says Trump, who wants to emphasize that migration represents the "single greatest threat" to US national security.
The president announces that the National Guard presence in Washington, D.C. will be further strengthened. More than 2,000 soldiers are already in place there – a controversial and contentious measure that is the subject of political battle – and another 500 are to be sent there.
After the incident, security was tightened at the White House, but Trump himself was in the state of Florida.
"We were targets"
The suspected perpetrator lives with his wife and five children on the other side of the country, in Washington state. Relatives who have been in contact with American media are shocked and horrified.
Afghanistan's army was built up by the US after its invasion. It fought alongside US soldiers against the Taliban and other resistance groups. The suspect arrived in the US in September 2021 - a few weeks after the US withdrew all forces from Afghanistan in chaotic conditions where the Taliban took back government power.
Many Afghans who were considered to be in particular danger at the time, due to their cooperation with the US and the Western countries involved, were helped to escape Taliban rule. According to AP information, the suspected shooter was one of these people.
Many other Afghans did not receive that help and remained behind.
