Two employees of the US Mission in Nigeria have been found "alive and safe" days after an attack on a US convoy left seven others dead.

The US Mission in Nigeria said Friday that those two employees were "under the protection of Nigerian authorities in Anambra," and that their families had been informed of their safe recovery.

"U.S. Mission personnel are on their way to meet and accompany them home," the mission said in a statement.

The other seven members of the convoy -- three other employees of the US Mission and four police officers -- were killed in the attack. All nine of the people in the convoy were Nigerian nationals, according to a statement from US Secretary of State Antony Blinken on Wednesday.

"We mourn the loss of our other steadfast colleagues and four police escorts, who were advancing humanitarian work in the region," US Mission Nigeria said in a tweet Friday.

The two car convoy was "traveling in advance of a planned visit by U.S. Mission personnel to a U.S.-funded flood response project in Anambra" when it was attacked by "unknown assailants" on Tuesday, Blinken said Wednesday.

"We do not yet know the motive for the attack, but we have no indications at this time that it was targeted against our Mission," he said at the time.

"We condemn in the strongest terms this attack. We will work closely with our Nigerian law enforcement colleagues in seeking to bring those responsible to justice," the top US diplomat said.

The US Mission said Friday that they were working "intensively with Nigerian security and law enforcement on this matter, to identify the victims previously found, and to bring to justice those responsible for this heinous attack."

"We welcome any information the public may have in this regard," the statement said.