Colombia on Friday said it will soon complete a U.S.-backed aerial fumigation campaign to wipe out coca fields near the border with Ecuador, after Ecuador's president-elect canceled a planned visit to Bogota to protest the spraying.

"In five or six days we will finish the fumigation," Colombian interior minister Carlos Holguin told Caracol radio, adding that more than 60 percent of the some 25,000 acres of coca fields in the border zone had already been sprayed.

But Gen. Jorge Baron, director of Colombia's anti-narcotics police, told The Associated Press that "if there are rains or strong winds, we can't fumigate, and the operation could be extended for more time."

Colombia renewed spraying on Dec. 4 to eradicate fields of coca, the plant used to make cocaine, to within 330 feet of the border because coca growers had swarmed into the area.

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Ecuadorean President-elect Rafael Correa, who takes office Jan. 15, has criticized the fumigation using the herbicide glyphosate, saying it kills legal crops on the Ecuadorean side of the border and has been blamed for causing health problems.

On Thursday, Correa canceled his trip to Colombia at the last minute in protest.

"With much pain, we have decided to suspend the visit to Bogota," Correa said in Caracas, Venezuela, at a joint news conference with leftist Venezuelan President Hugo Chavez. Correa had been scheduled to fly from Venezuela's capital to Bogota Thursday evening.

Chavez staunchly backs Correa in saying that Colombia should find another way to stamp out cocaine production. The two are united by leftist ideology and critical stances toward the United States — a sharp contrast with Colombian President Alvaro Uribe, one of Washington's closest allies in South America.

On Friday, Holguin suggested that Correa's change of plans may have been influenced by Chavez.

"President Correa had a change of opinion after interviewing with President Chavez," he said.

Colombian Foreign Minister Maria Consuelo Araujo told Caracol radio that Correa had notified Bogota "through the media" of a previously unmentioned condition that Colombia suspend the fumigation during his visit.

Ecuador already calling home its ambassador to Colombia for consultation on the spraying and asking the Organization of American States and the United Nations to intervene.