WASHINGTON — Three Pakistani nationals pleaded guilty before a US court Monday to terrorism-related charges of supporting the Pakistani Taliban, Justice Department officials said.

At a hearing before US District Judge John Bates in Washington, the three -- Irfan Ul Haq, 37; Qasim Ali, 32; and Zahid Yousaf, 43 -- each pleaded guilty to one count of conspiracy to provide material support to a designated foreign terrorist organization.

At sentencing set for December 9, each faces a maximum sentence of 15 years in prison and a fine of up to $250,000.

As part of their plea agreements, the three have agreed to be sent back to Pakistan upon the completion of their sentences.

"These defendants sought to smuggle someone they believed to be a member of a terrorist organization from halfway around the world into the United States," said Assistant Attorney General Lanny Breuer.

"For financial profit, they were willing to jeopardize the safety and security of the American people."

The three were arrested in Miami on March 13 on an indictment charging them with one count of conspiracy to commit alien smuggling.

Officials said the three, who were suspected of running an alien smuggling operation from Ecuador, were targeted by an undercover operation in which agents asked them to smuggle in a person said to be linked to the Tehrik-e Taliban Pakistan (TTP), also known as the Pakistani Taliban, to the US.

They accepted payment from the confidential sources for the smuggling operation and obtained a false Pakistani passport for the purported TTP member and agreed to help him come to the US.

According to the court documents, the defendants told the confidential sources that it was "not their concern" what the man wanted to do in the United States.

The investigation was conducted by the Homeland Security attache office in Quito, with the FBI and Ecuadoran national police.