American aid worker killed in Baghdad in rare attack

LONDON -- An American aid worker was gunned down in Baghdad on Monday, officials said.

Millennium Relief and Development Services, a Texas-based international aid group, confirmed in a statement that one of its workers was "shot and killed by armed attackers as he returned to this home on Monday evening." His name has not yet been released.

"We are greatly saddened by the tragedy that took the life of our colleague, near his home in Baghdad, Iraq," Millennium said. "An investigation is ongoing and details on the assailants and the motivation for the attack are not known at this time."

The victim had worked for the past few years for Global English Institute, a local English learning institute that Millennium said has operated under its umbrella for more than two decades. He was in charge of "managing the promotions and advertising while his wife was manager of the school," according to Millennium.

"He loved the people of Iraq and it motivated him to strive for excellence in his work at Global," Millennium added. "He will be remembered as a source of great encouragement and will be missed by all who knew him and were touched by his life.”

There was no immediate claim of responsibility for the killing.

Attacks against individual foreigners in Baghdad were common in the early years that followed the United States-led invasion of Iraq in 2003. Such incidents have been rare since the territorial defeat of the Islamic State group in Iraq in 2017, according to The Associated Press.

In January, rockets were fired toward the U.S. Embassy in Baghdad's heavily fortified Green Zone.

U.S.-led coalition forces concluded their combat mission in Iraq last year, but American troops remain there to advise and train Iraqi forces in the ongoing fight against ISIS.

ABC News' Cindy Smith contributed to this report.