The US Attorney's Office on Thursday said 69-year-old Moses Slanger Wright, a former commanding general of the Armed Forces of Liberia who has been residing in Philadelphia, had been charged with fraud and perjury in relation to his attempts to obtain US citizenship.

"The defendant, when applying for US citizenship, was not truthful about his activities during Liberia's First Civil War," it said in a statement.

The indictment accuses Wright of either personally committing or ordering soldiers to commit "numerous atrocities", including murdering, assaulting, persecuting, falsely arresting and imprisoning civilians.

Wright was arrested Thursday and made his first appearance in federal court the same day, a spokeswoman for the US Attorney's Office said.

If convicted, he faces a maximum possible sentence of 165 years in prison and a $7,000,000 fine.

Liberia's Truth and Reconciliation Commission has accused Wright and others of massacring 27 Mano and Gio civilians in June 1990.

Liberia's first civil war raged from 1989 to 1997 and, together with the second civil war from 1999 to 2003, claimed around a quarter of a million lives.

The Liberian army fought various rebel groups, including Charles Taylor's National Patriotic Front of Liberia.

Despite regular appeals to establish a war crimes court, very few people have faced trial for war crimes or crimes against humanity committed in Liberia.

"Those who took innocent people's lives during the civil war -- those who heartlessly killed kids, tortured the elderly ones -- need to face justice," Adama Dempster, a Liberian rights campaigner, told AFP after the news of Wright's arrest.

The former army commander was granted asylum in the United States in 2000, and in 2013 applied for citizenship.

According to the US Attorney's Office, his application included false denials, including over whether he had ever persecuted any person because of race, religion or political opinion, and whether he had ever commited a crime or offence for which he was not arrested.

"Wright sought to escape to the United States and start anew, where he lied about his appalling wartime conduct on federal immigration forms and to the faces of US officials," United States Attorney Jacqueline Romero said.

His case is the fourth public criminal prosecution in Philadelphia in connection with the Liberian civil wars, according to rights group Civitas Maxima.