By JASON WEBB
  Reuters

  BOGOTA, Colombia - Suspected leftist rebels went on a bombing offensive in Colombian cities and wrecked a small town airport on Monday as the nation braced for a violent run-up to Wednesday's presidential inauguration.

  Just two days before President-elect Alvaro Uribe is due to assume control of a government he promises will crack down on Marxist guerrillas, suspected rebels planted bombs in the cities of Cartagena and Medellin and wrecked a small town airport.

  Shocked office workers, some weeping, staggered from the provincial government offices in the historic old town of Cartagena, one of Colombia's main tourist
  attractions, after a bomb blew a hole in a third-story wall and seriously hurt three people. Three bombs blew up in separate parts of the city of Medellin, causing minor damage to buildings.

  Suspected members of the Revolutionary Armed Forces of Colombia, or FARC, also launched homemade mortar bombs at the town airport in Saravena, Arauca
  Province, the army said.

  The bombs, crudely made out of old gas canisters, packed with explosives and fired from metal cylinders, smashed into the terminal at about 10 a.m., wounding 12
  civilians and six soldiers.

  "The explosives almost completely destroyed the airport installations. Three of the six soldiers hurt are gravely injured," an army spokesman said.

  Right-winger Uribe won a landslide election victory in May, promising increases in military spending to get to grips with a 38-year-old war that claims thousands of lives a year.

  Uribe swept into office on a wave of popular discontent over attempts by outgoing President Andres Pastrana to talk peace with the FARC. The peace process collapsed in February and Uribe says he will use force to push the rebels back to the negotiating table, a process expected to take years.

  He also promises to hit far-right paramilitary militias, which, like the FARC, draw much of their funding from Colombia's cocaine trade, the world's biggest.

  Uribe, whose father was shot to death by the FARC in the early 1980s, narrowly escaped death himself in April when a bomb buckled his car and killed three people in the coastal city of Barranquilla.

  SOLDIERS ON ALERT, U.S. PLANE TO OVERFLY BOGOTA

  In attacks apparently timed to coincide with Uribe's taking office, three bombs exploded in the Andean capital Bogota over the weekend, although only one person - apparently a bomber accidentally caught by his own blast - was killed.

  Police also arrested six suspected FARC commandos they said were planning attacks to disrupt the inauguration. They seized a number of weapons from the six,
  including a 60 mm mortar.

  The security forces have put 220,000 soldiers and police on alert throughout the country and the United States says one of its surveillance planes will overfly Bogota during Wednesday's ceremony to enforce a no-fly zone.

  Police said in July they had uncovered a FARC plot for a suicide pilot to crash into a Bogota target, possibly during Uribe's swearing-in.

  Uribe is a keen proponent of military aid from the United States, which has provided Colombia with more than $1.5 billion in anti-drug assistance over the past four
  years.

  Nerves over the possibility of more attacks hurt the peso, which lost 0.8 percent of its value on Monday to close at 2,666 per U.S. dollar.

  Violence is common in killing- and kidnap-plagued Colombia, but usually occurs in the countryside far from the relative order of tidy Bogota.

  Saravena is a small town surrounded by jungle disputed by the FARC, a smaller Marxist rebel group and the paramilitaries. Police, afraid of being shot at on the streets, seldom venture far from the sandbags protecting their barracks and the rebels are so self-confident they have put up billboards on a highway just a short drive out of town.

  Arauca is strategically vital for its oil wealth. Suspected rebels have once again sabotaged the country's second-largest oil pipeline, the Cano Limon, the state oil
  company Ecopetrol said on Monday. The pipeline transports oil from a field near Saravena operated by U.S. firm Occidental Petroleum.