Federal law enforcement officials said they are charging a 23-year-old Michigan man with possessing explosive devices that he planned to ignite at the Republican National Convention.

Matthew Bradley DePalma of Flint, Mich., possessed five homemade Molotov cocktails when he was arrested in a Minneapolis apartment on Aug. 28, according to the U.S. attorney from Minnesota.

Officials said DePalma planned to set off explosives in tunnels near the convention hall to destroy electrical cables and cause a power outage on either the first or final night of the event. He is charged with one count of possessing unregistered firearms, which could bring a 10-year prison sentence, and is scheduled to appear in federal court in Minneapolis on Friday.

After two days of clashes between police and protesters outside the Republican National Convention, officials said they will be carefully watching a Rage Against the Machine concert in Minneapolis tonight for trouble.

Officials said their preparation has included bringing in former Los Angeles Police Deputy Chief Michael Hillman for advice. Hillman, a former SWAT squad supervisor and member of the Los Angeles force’s anti-terrorism squad, was put in charge of the city’s antigang efforts in 2002.

“We are ready for today,” St. Paul Police Chief John M. Harrington said. “We have a plan in place.”

Harrington said there were 11 more protest-related arrests Tuesday, bringing the total to 305. Harrington said seven of those arrested Tuesday were identified from video as suspects in the smashing of windows in police cars and at a downtown department story on the first day of the convention, while three others were caught carrying bags of feces, urine and bricks to a rally at Mears Park on day two.

Rage Against the Machine, which tends to draw politically active fans, has already been factored into security plans. The band, which was told it could not play a rally in St. Paul, began an impromptu concert Tuesday on the grounds of the state Capitol. Police quickly shut it down.

Singer Zack de la Rocha told assembled fans that the band does not condone violence of any sort. However, some people in the audience ended up in a crowd that baton-wielding police later dispersed downtown with pepper spray, tear gas and flash bangs.

St. Paul officials faced a noon deadline today to bring charges against 170 protesters arrested earlier this week or let them go. Harrington said police were still having trouble identifying protesters who refused to provide their names, but expected to be able to bring charges.

He said the protests in the city have become more restrained as the week has gone on, and that security forces have faced challenges.

“I certainly think we were tested,” he said. “The rioters came at us very heavy on day one.”

Police have credited organizers of the main protests this week with keeping order and have blamed the violence on small groups of anarchists and other troublemakers. The violence helped to kill plans for a parade through St. Paul by about 200 18-wheel trucks, designed to draw attention to the impact of high fuel prices on truckers.