TOLEDO, Ohio — Two brothers admitted in federal court on Thursday that they sent $17,000 to an al-Qaida leader who they knew was planning terrorist attacks.

They are the last of four defendants to plead guilty in what prosecutors say was a scheme to collect money through fake credit card transactions and other means to support terrorism.

Asif Salim, 37, and Sultane Salim, 43, both pleaded guilty in federal court in Toledo to concealing the financing of terrorism.

Prosecutors agreed to drop more serious charges, including conspiracy to provide material support to terrorists, against the pair in exchange for the pleas. Both face sentences of up to eight years in prison, according to the plea deal.

Federal prosecutors have said in court documents that the four men raised nearly $30,000 for Anwar al-Awlaki, considered an inspirational leader of al-Qaida before he was killed in a drone strike in Yemen in 2011.

U.S. officials linked him to the planning and execution of several attacks targeting American and Western interests.

Michael Freeman, an assistant U.S. attorney, said Sultane Salim, who lived in the Columbus area, provided $15,000, while Asif Salim, who had attended Ohio State University, gave $2,000 that was eventually delivered to Awlaki.

Sultane Salim’s attorney, Cherrefe Kadri, said she could not say much about the case until sentencing is completed.

On Wednesday, Ibrahim Zubair Mohammad, an Indian citizen, also pleaded guilty to concealing the financing of terrorism.

He collected the money from the Salim brothers, Freeman said, and then deposited it in his brother’s bank account in the Toledo area.

Mohammad’s brother, Yahya Farooq Mohammad, then arranged for the money to get to Awlaki, Freeman said.

Yahya Farooq Mohammad, also an Indian citizen, was sentenced in November to 27 years in prison after pleading guilty to supporting terrorism and trying to arrange the killing of a federal judge overseeing his case.