Defying the burning tires and chants against him, rock star Ammar Hassan was ushered on stage 45 minutes late by bodyguards on Tuesday night.
He opened his show with a song about "holy Jerusalem" in an apparent effort to appease the armed men. Less than an hour later, however, guards whisked him off stage.
Hassan became a Palestinian sensation when he won second place in the 13-week Superstar 2 competition on Lebanese TV channel al-Mustaqbal last year.
Tuesday's concert was the opening of a shopping festival meant to bring a bit of normality to the largest city in the West Bank, hard hit by Israeli army operations and curfews in more than four-and-a-half years of Israeli-Palestinian violence.
Nablus and its An-Najah University, where the concert was held, is known as a stronghold of the resistance.
The interruption of the concert was the latest sign of growing chaos in the Palestinian areas.
Armed men have gained increasing control of the Palestinian street during the four-and-a-half years of conflict as Palestinian security forces have been weakened.
Armed men have gained more
control of the Palestinian street
About 1500 fans showed up for the concert, eager to see the singer who is known throughout the Arab world and was born in the nearby town of Salfit.
When armed men of the al-Aqsa Martyrs Brigades - an armed wing linked to the ruling Fatah party - began shooting in the air, Hassan's arrival from a nearby hotel was postponed.
"This is the not time to have parties like this in Nablus," said one of the masked armed men, who would not give his name.
"We lost a lot of martyrs and lost a lot of friends, and this is not appropriate for Nablus," he added.
About 20 people who said they were members of the resistance group Hamas held signs reading: "Don't dance on our blood."
Palestinian policemen did not make any moves to arrest the armed men but tried to persuade them to calm down.
Hassan sang a few songs, most of them with hints of political themes and one about love. He ended the concert much sooner than planned, and then guards, concerned for his safety, hustled him to a bulletproof room.
When Hassan refused to answer calls to come back on stage, his fans began turning over chairs to demand his return.
"We lost a lot of martyrs and lost a lot of friends, and this is not appropriate for Nablus"
Unidentified armed man
"I am depressed," said concert-goer Qassem Ewais, 21, who travelled around Israeli army roadblocks from the West Bank town of Qalqiliya.
"I came to dance and sing and suddenly armed men surrounded the university... These people are criminals. They are liars."
The concert ended with a brawl between opponents and supporters of the show throwing chairs at each other.
Then shouting erupted between armed university guards and policemen, but no shots were fired and no injuries were reported.
Hassan had sung in recent days with great success to large crowds in the more secular towns of Ram Allah and Bethlehem.