DETROIT — An undercover federal agent infiltrated a Christian militia group that authorities say plotted to incite violent revolt, and the agent built explosives under the direction of the group's suspected ringleader, a prosecutor said Wednesday.

Arguing for the detention of alleged Hutaree leader David Brian Stone, 44, and six other members, Assistant U.S. Attorney Ronald Waterstreet said the agent accompanied Stone and others in a van as they tried to attend a Feb. 6 meeting of militias in Kentucky.

They turned back in Indianapolis because of bad weather, but the agent recorded Stone reading a speech, Waterstreet said. In the recording, played in U.S. District Court in Detroit, a speaker identified as Stone says "now it's time to strike and take our nation back so we will be free of tyranny."

Prosecutors say the group planned to make a false 911 call, kill responding police officers, then set off a bomb at the funeral to kill many more. An indictment said that after the attacks, the group planned to retreat to "rally points" protected by trip-wired explosives for a violent standoff with law enforcement personnel.

Several defense attorneys objected to Waterstreet's testimony. "All they're saying is my client has an opinion and knows how to use his mouth," Stone's lawyer William Swor said before Waterstreet played the tape.

Later on the drive back to Michigan, Waterstreet said the van carrying the militia members passed a car on the side of the road with a Hudson, Mich., police car behind it, and Stone said "We're going to pop him — guaranteed."

Nine suspected members of Hutaree, self-proclaimed "Christian warriors" who trained themselves in paramilitary techniques in preparation for a battle against the Antichrist, were arrested after a series of raids across the Midwest.

All have been charged with seditious conspiracy, or plotting to levy war against the U.S.

Federal officials said they began monitoring the militia last summer and they believed an attack was planned for April. Waterstreet said Hutaree was planning training that month where they would kill people that "came upon them." Court documents said an undercover FBI agent and a cooperating witness were part of the federal probe.

Eight suspects were arraigned Wednesday in Detroit. U.S. District Court Magistrate Judge Donald A. Scheer entered not guilty pleas on behalf of seven of them, who stood mute to the charges, including David Brian Stone. Stone's eldest son, 21-year-old Joshua Matthew Stone, was the only one who spoke up. He pleaded not guilty.

The ninth suspect appeared in court in Indiana but no plea was entered.

In arguing for detention, Waterstreet told the court the suspects' conduct was at issue.

"It's not about a religious group," Waterstreet said. "It's not about the militia. It's about a group who decided to oppose by force the U.S. by using violence and weapons."

Waterstreet described the hierarchy of Hutaree, saying David Brian Stone led the militia and Joshua Matthew Stone was a squad leader. He said David Brian Stone Jr., the elder Stone's 19-year-old son, was in charge of detonations and explosives.

He said Kristopher Sickles, 27, of Sandusky, Ohio led the militia in that state and that others charged in the case had responsibilities including communications and recruitment. He said Michael David Meeks, 40, and Thomas W. Piatek, 46, of Whiting, Ind. were "heavy gunners" in charge of "laying down heavy fire" in encounters with the enemy.

In Indiana, Judge Paul Cherry ordered Piatek held without bond and that he be transferred to Michigan to face weapons and conspiracy charges with the other defendants.

A federal prosecutor testified that FBI agents found 46 guns and 13,000 rounds of ammunition in Piatek's home in Whiting, Indiana.

Defense attorney Jerry Flynn said Piatek denies he planned to participate in the alleged plot.

Hearings to determine if any of the defendants would be released on bail were being held Wednesday afternoon for leader David Stone and six others.

Meeks was expected to face a detention hearing Thursday. A lawyer for Meeks said evidence would be presented that distinguishes him from the other defendants, and that he denied involvement in any plot to overthrow the government.