FERGUSON, Mo./WASHINGTON, Feb 10 (Reuters) - The U.S. Justice Department filed a civil rights lawsuit against Ferguson, Missouri, on Wednesday to enforce a police and court reform plan after the city said it wanted to amend some aspects of a consent decree it had reached with the federal agency.
SEE ALSO: Police make tragic find in hunt for missing 3-year-old
The Justice Department initiated a civil rights investigation into Ferguson's policing after an unarmed black teenager was killed by a white police officer in 2014. It resulted in a report that was extremely critical of Ferguson's police and court systems.
"The residents of Ferguson have waited nearly a year for their city to adopt an agreement that would protect their rights and keep them safe," Attorney General Loretta Lynch said at a news conference.
She said the agreement that was decided upon had been painstakingly negotiated and Ferguson officials knew that rejecting it would invite litigation.
See photos from Ferguson in the height of crisis in 2014:
Earlier on Wednesday, Ferguson officials said they wanted to negotiate further with the Justice Department over police reforms, after voting on Tuesday to amend the agreement.
Mayor James Knowles told a news conference that reforms had to be affordable and attainable. "It serves no one's purpose for us to fail," he said.
Ferguson's city council voted on Tuesday to accept the reform agreement, called a consent decree, subject to conditions, including that it not be required to increase police officers' pay and police staffing levels. It also said it wanted more time to comply with the other terms.
The city became a symbol of problems with policing and race in the United States after 18-year-old Michael Brown was killed by Ferguson Police Officer Darren Wilson in August 2014.
It was one of several killings of black men, mostly by white officers, that started a nationwide debate about the use of excessive force by police, especially against minorities.
SEE ALSO: Sanders raises huge amount of cash after NH win
Knowles said that only in the last two weeks had the city been able to analyze the costs of implementing the decree.
He and city council members said Ferguson had already made some reforms, including community policing and a civilian review board to oversee police.
Civil rights advocates warned that litigation with the Justice Department could cost more than implementing the agreement.
"This decision only creates the potential for the type of litigation that creates more financial challenges that will be a burden on poor people," said Rashad Robinson, executive director of Color of Change, a national civil rights organization.
(Reporting by Sue Britt and Julia Edwards; Additional reporting by Ben Klayman; Writing by Fiona Ortiz; Editing by Toni Reinhold)
More from AOL.com:
Lawyer receives hundreds of texts from strangers wanting free chipotle
Alaska Airlines flight diverts to Denver after passenger threatens crew
Hillary Clinton to hire former Obama deputy campaign manager