(MSNBC) -- A Texas man pleaded guilty Wednesday to plotting to assassinate Saudi Arabia's ambassador to the United States, acknowledging he agreed to hire what he thought was a drug dealer in Mexico last year for $1.5 million to carry out the attack with explosives at a Washington, D.C., restaurant.
Manssor Arbabsiar, 58, entered the plea to two conspiracy charges and a murder-for-hire count in U.S. District Court in Manhattan. Judge John F. Keenan repeatedly asked Arbabsiar whether he intended to kill the ambassador. Arbabsiar, a U.S. citizen who holds an Iranian passport, said he did.
"I take responsibility for my actions," Arbabsiar said.
Arbabsiar also admitted he agreed to help transfer more than $100,000 through a New York bank to help further the plot.
When Arbabsiar's arrest was announced last year, President Barack Obama's administration accused the Iranian government of being behind the planned assassination of Ambassador Adel al Jubeir in Washington.
The press attache at Iran's mission to the United Nations then called the accusation "baseless."
"Mr. Arbabsiar's plea today confirms what our investigation had already uncovered: that he plotted to murder the Saudi Ambassador with members of Iran's elite Qods Force," said FBI Acting Assistant Director Mary Galligan. "The FBI remains ever vigilant toward acts of terror both here and abroad."
Authorities say Arbabsiar earlier admitted his role in a $1.5 million plot to kill the ambassador at a restaurant by setting off explosives.
Sentencing is scheduled Jan. 23. Arbabsiar faces up to 25 years in prison. A trial had been scheduled for January.
Arbabsiar, who lived in Corpus Christie, Texas, for more than a decade, said he went to Mexico last year to meet a man named Junior, "who turned out to be an FBI agent." He said that he and others had agreed to arrange the kidnapping of ambassador Al-Jubeir, but Junior said it would be easier to kill the ambassador.
Arbabsiar has been held without bail since he was arrested Sept. 29, 2011 at John F. Kennedy International Airport. He was brought into court Wednesday in handcuffs. He spoke English and did not use a translator, despite saying he understood only about half of what he read in English. Bearded and bespectacled, he smiled several times during the proceeding, including in the direction of courtroom artists who were seated in the jury box when he entered court.
Defense lawyers say Arbabsiar suffers from bipolar disorder.
Assistant U.S. Attorney Edward Kim said that if the government had proceeded to trial, it would have presented a jury with secretly recorded conversations between Arbabsiar and a confidential source, along with Arbabsiar's extensive post-arrest statement to authorities and emails and financial records.
Authorities have said they secretly recorded conversations between Arbabsiar and an informant with the Drug Enforcement Administration after Arbabsiar approached the informant in Mexico and asked his knowledge of explosives for a plot to blow up the Saudi embassy in Washington. They said Arbabsiar later offered $1.5 million for the death of the ambassador.
A second person, Gholam Shakuri, was charged in the plot but remains at large in Iran.
The Justice Department said Shakuri is an Iran-based member of Iran's Qods Force, which is a special operations unit of the Iranian Islamic Revolutionary Guard Corps that is said to sponsor and promote terrorist activities abroad.