Jair Diaz is one of the brave ones. After leftist rebels gunned down two city councilmen, most other politicians fled this town in the shadow of Colombia's rebel-controlled southern jungles.

Despite death threats and pleas from his family, the 36-year-old accountant refuses to drop his mayoral bid.

"The assassins trying to kill me are also afraid," Diaz said coolly as he canvassed for votes while his four armed bodyguards kept a constant eye on passing motorbikes.

Election-related violence is soaring in rural Colombia ahead of Sunday's local and regional elections. Twenty candidates have been assassinated the past two months, almost all of them attacks carried out by leftist rebels against allies of conservative President Alvaro Uribe.

An independent consortium of academics says ballots are in jeopardy in half the country's 1,098 municipalities, where violence has curbed campaigning and fear is expected to keep many voters home on election day.

The killings worry Uribe, whose policies are credited for a nationwide drop in homicides and kidnappings but haven't slowed attacks on political candidates. He acknowledged the danger during a visit to El Doncello on Tuesday, saying that "terrorists have managed to cause damage."

However, Uribe said, "The terrorists can't alter the democratic will of the Colombian people, who will head to the ballot boxes Sunday to express themselves in unprecedented numbers."

Political life has long been fraught with danger in Colombia, where violent right-wing paramilitaries and organized crime groups also operate. Some opposition candidates have asked that the vote be delayed. The government has called the safety worries exaggerated.

The Interior Ministry has provided bulletproof vests, armored vehicles and bodyguards for 131 candidates in high-risk areas, and all such politicians have so far escaped harm.

"But it's impossible to provide a bodyguard and armored SUV to all 87,000 candidates," said Maria Isabel Nieto, the deputy interior minister. "Candidates also need to do their part and avoid exposing themselves too much."

That's not easy in places like El Doncello, where half the 24,000 residents live in isolated hamlets where guerrillas roam freely. On July 10, leftist rebels targeted the town's 11 councilmen, killing two. Quick police reaction and luck — three councilmen were traveling and several were at a church event — prevented a higher death toll.

The surprise attack — along with a January car bombing that flattened a dairy plant, forcing Swiss food giant Nestle SA from town — disrupted what the rebels call a sham democratic process.

Today, town business is done by telephone and the Internet. Most councilmen fear the Revolutionary Armed Forces of Colombia, or FARC, will pursue their relatives. Only one councilman is seeking re-election; the others have left Caqueta state.

A typewritten threat shoved under Diaz's door described their predicament well: "There's no corner of Caqueta left where you won't be hunted down."

"Even if we have to go hungry, I'm not going back," said councilman Luis Gonzago Murcia, who now supports his wife and four children by working construction and selling pirated CDs in Bogota, the national capital. "I know it's bad, but I have to feed my family."

Uribe decided to go to El Doncello after an Oct. 12 roadside bombing nearly killed Sen. Luis Fernando Velasco. "The response of El Doncello to this bad news caused by the FARC attack on Sen. Velasco has to be a mass rush to the polls next Sunday," Uribe told the crowd.

But just as the president boarded a helicopter for Bogota, masked gunmen presumed to be from FARC killed two more candidates in a neighboring municipality.

Vice President Francisco Santos has accused the rebels of trying to meet a kill quota to show their muscle locally as their national power erodes.

In their sights are people like mayoral candidate John Edward Monje in the town of Milan. Traveling by river to a campaign event Oct. 21, his floating caravan was ambushed by six guerrillas. He paddled furiously and then swam to safety under heavy fire, but an aide and bodyguard were killed.

Monje has dedicated his campaign to them: "They can kill me, but the FARC will never assassinate our democracy or the ideals I believe in."