SAN FRANCISCO - After a day of hobnobbing with dozens of his wealthiest patrons, President Obama took his case for a second term before a boisterous crowd of 2,900 low-dollar donors who filled the Nob Hill Masonic Center here for a concert and speech.

"I'm here not just because I need your help, San Francisco," Obama told the raucous crowd that had peppered him with shouts of affection from the moment he took the stage. "I'm here because this country needs your help."

"We love you," someone later shouted from the balcony.

"I've told you I love you already," Obama said with a characteristic grin and a chuckle, drawing laughter from the crowd.

But the reception wasn't entirely warm.

Obama was interrupted twice by critics of his policies who raised their voices and rushed toward the stage before they were removed.

As Obama hailed the end of the Iraq war and efforts to "focus on the terrorists" in Afghanistan, one woman stood and shouted repeatedly, "stop the killing of innocent civilians in Afghanistan and Pakistan."

She was swiftly pushed out of the auditorium by an event worker and police officer.

Later, as Obama spoke about regulatory protections put in place under his administration, another guest stormed down one of the aisles shouting. "We don't want deepwater drilling here," she yelled as a police officer nudged her to the exit.

Obama made light of the episode.

"This is what San Francisco is always about," he said, drawing laughter and applause. "There's always something going on in San Francisco. Folks are not shy about sharing their ideas in San Francisco. It's fun."

An estimated 2,500 supporters filled the bi-level auditorium, each forking over at least $100 to the Obama Victory Fund, according to a campaign official.

Chris Cornell of Soundgarden provided entertainment before the president's arrival, singing as part of his set John Lennon's "Imagine" and a rendition of Dolly Parton's "I Will Always Love You," in a nod to Whitney Houston, who popularized the song.