KWANGJU, SOUTH KOREA, NOV. 14 -- Thousands of angry protesters hurled wood, eggs, rocks and insults at Kim Young Sam today, forcing the South Korean presidential candidate to flee a campaign appearance in the political heartland of his rival, Kim Dae Jung.

Riot police were notably absent during more than an hour of the disturbances, and many people at the scene later charged that provocateurs sparked the incident, the most serious outbreak of violence in South Korea's presidential campaign since dozens of firebombs were hurled at ruling party candidate Roh Tae Woo last month.

"Citizens of Kwangju, why are you doing this?" Kim Young Sam shouted as he ducked projectiles thrown at him by youths who hurled almost anything they could get their hands on. Wooden placards bearing Kim's picture, rotten fruit and even a shoe were launched at the presidential candidate, who spoke for less than two minutes before being rushed out of the plaza of the train station by security guards.

As Kim tried to speak, his campaign leaflets were being tossed into bonfires that dotted the area. Scuffles broke out and grew more intense as the disturbance continued.

"This will only help {President} Chun Doo Hwan and Roh Tae Woo," Kim Young Sam pleaded before being forced to flee. "We should be chanting together, 'Democracy Forever.' "

Rocks were thrown at his black sedan as it sped off through a back alley. Kim's panicky aides sprinted from the scene, commandeering cars or trucks.

At least seven persons were reportedly injured in the clashes, including a photographer who was hospitalized with a head wound.

More than 20 persons were arrested when hundreds of riot police finally moved in, firing tear gas, long after Kim had left the area and the violence had calmed down. Most of those arrested appeared to be students.

Today's disturbance is in keeping with a recent trend of sharpening antagonism between the country's disadvantaged southwestern region, political base of opposition candidate Kim Dae Jung, and the more affluent southeastern region, home of Reunification Democratic Party candidate Kim Young Sam and Democratic Justice Party candidate Roh.

Kim Young Sam's rally here in the capital of Kim Dae Jung's home province of South Cholla appeared doomed from the start. Two weeks ago, on a campaign visit to Kim Young Sam's home province of South Kyongsang, Kim Dae Jung faced a violent protest by several hundred youths at a hotel in the port city of Pusan. It had been predicted -- correctly, as it turned out -- that Kim Dae Jung's supporters in Kwangju would seek revenge today, although the scale of the violence was not anticipated.

The two opposition rivals had been partners in a political marriage of convenience against Chun. But their shaky relationship broke apart once they had to decide which one of them would run against Roh, a former general who was handpicked by Chun to be the ruling party candidate, in the presidential elections now set for Dec. 16.

The two Kims formally split last month, when each declared separate candidacies for president and Kim Dae Jung formed his own opposition party.

It is assumed that the provocations involve largely the two opposition candidates' own firm supporters. Thus, the campaign violence is viewed as detrimental to the two Kims and advantageous to Roh, because the disturbances could make some undecided voters wary of the opposition, and Roh presumably would attract those fence sitters.

Kim Dae Jung stands to suffer the most, since the violence could reinforce his reputation as a radical with uncontrollable supporters.

The violence today was given extensive coverage on state-controlled television stations, which the two Kims recently have accused of biased reporting because the opposition usually receives little coverage. Roh typically is featured at the beginning of the stations' newscasts.

But today, top billing was given to the disturbance here, along with the extensive footage of the violence.

The violence was quickly condemned by the opposition. Kim Dae Jung called it "extremely regrettable." One aide to Kim Young Sam said it was "a profound tragedy"; another adviser called it "disgusting."

{According to Reuter, Roh's party expressed "deep worries and regret" over the violence, which it said "proved that regional antagonisms can reach a dangerous point." President Chun, who as an Army general seized power in a 1979 coup, told his Cabinet that "we are seeing a replay of the evil characteristics of the direct election system."}