In a press briefing on Monday, State Department spokesman Matthew Miller said the statement issued by the department's Bureau of Near Eastern Affairs “made clear our position on terrorist attacks”.
“It made clear our position on extreme settler violence,” Mr Miller added.
He also said an Israeli army representative had also referred to the attack as “nationalist terrorism”.
“We have also been clear that accountability and justice should be pursued with equal rigour in all cases of violent extremism, whoever the perpetrators are,” Mr Miller said.
The bureau on Sunday called for “full accountability and justice” for the murder of Qusai Maatan, who was shot dead by Israeli settlers in the occupied West Bank village of Burqa near Ramallah on Friday.
Asked whether the US would take any action after the incident, Mr Miller said that that Israeli authorities had made arrests and were “seeking to hold the perpetrator accountable”.
“That's an appropriate action.”
Israeli newspaper Haaretz reported that two suspects had been charged with “deliberate or depraved-indifference homicide” with a racist motivation.
Settler attacks against Palestinians and vice versa have increased in recent months. Some of the Palestinians affected by the attacks hold US citizenship.
The US statement on Mr Mataan's killing was issued together with a second statement, which condemned as terrorism a Palestinian gun attack that killed a security officer in Tel Aviv.
Far-right Israeli Police Minister Itamar Ben-Gvir said on social media that Palestinian stone-throwers had “tried to murder Jews” in Burqa and demanded that they be fully investigated.
Israel's Army Radio reported that the rate of attacks by settlers or their supporters against Palestinians in the West Bank had more than doubled this year compared to 2022.
“We are faced with the evolution of a dangerous Jewish nationalist terrorism,” opposition politician Benny Gantz, a former defence minister, said on the messaging platform X, formerly known as Twitter.
With additional reporting by Reuters