March 6 (Bloomberg) -- Colombian rebels bombed an oil pipeline and Venezuelan President Hugo Chavez said he may seize assets of the neighboring country's companies after a Colombian raid into Ecuador killed a rebel leader.

The bombing and Chavez's nationalization threats may be the start of reprisals for the March 1 air raid on Ecuadorean soil that killed the second-in-command of Colombia's biggest guerrilla group. Escalation of the conflict could cut the more than $5 billion in annual trade between Venezuela and Colombia.

``This is definitely the beginning of reprisals against Colombia and it is likely to continue,'' Edgar Jimenez, an equity analyst at Stanford Bolsa y Banca in Bogota, said in a telephone interview.

The Revolutionary Armed Forces of Colombia, known as the FARC, bombed the Transandino pipeline in Putumayo province, putting it out of service for at least three days, Colombia's Vice Minister of Mining and Energy Manuel Maiguashca said.

Owned by state oil company Ecopetrol SA, the pipeline brings petroleum from fields in Colombia and Ecuador to an export facility in Tumaco in Narino province on Colombia's Pacific coast.

Crude oil for April delivery rose 98 cents, or 0.9 percent, to $105.50 a barrel at the 2:30 p.m. close of floor trading on the New York Mercantile Exchange.

International Reaction

Nicaragua's President Daniel Ortega said today his country was joining Ecuador in breaking diplomatic relations with Colombia. Chavez, during a news conference last night in Caracas, asked his ministers to draw up an inventory of Colombian assets in Venezuela.

``Some of them could be nationalized,'' Chavez said. ``We're not interested in Colombian investments here.''

Ecuador's President Rafael Correa, who joined Chavez at the press conference, called on the international community to condemn Colombia for its cross-border strike. He said he'll only accept the findings of a panel set up by the Organization of American States to investigate the attack if it denounces Colombia's actions.

``If the international community doesn't condemn this aggressor without question, then Ecuador will know how to respond,'' Correa said.

Pipeline Attacks

U.S. Secretary of State Condoleezza Rice called on the countries to reach a diplomatic agreement over the border raid. She called Colombia a ``good friend.''

``Everybody needs to be vigilant about the use of border areas by terrorist organizations like the FARC,'' Rice told reporters after a meeting of North Atlantic Treaty Organization foreign ministers in Brussels.

Attacks on oil pipelines, including the Transandino, which carries about 60,000 barrels a day, have declined as Uribe boosts security near oil fields.

One Colombian field, Cano Limon, was hit 170 times in 2001, a figure that fell to 34 in 2003, the most recent year when figures were reported. The Transandino was attacked 30 times in November 2003, according to the Ecopetrol Web site.

Mobilizing Troops

Argentine President Cristina Fernandez de Kirchner met her Venezuelan and Ecuadorean counterparts today in Caracas.

``No one can agree with what Colombia did,'' Argentine Cabinet Chief Alberto Fernandez said in an interview on Radio 10 in Buenos Aires today. ``This is a violation of sovereignty that worries and infuriates us.''

Chavez, who calls the U.S. the ``empire'' and refers to President George W. Bush as ``Mr. Evil,'' said the U.S. was behind the attack. Colombian President Alvaro Uribe, in contrast, calls the U.S. ``a friend.''

Chavez and Correa, both self-proclaimed socialists, sent troops to their respective borders with Colombia this week to increase security.

An expanded military presence along the frontier -- already rife with paramilitary, drug trafficking and rebel activity -- raises tensions to a level where a miscalculation could trigger a military clash.

Colombian Companies

Grupo Nacional de Chocolates SA, Colombia's largest food company, stands to lose the most among publicly traded companies, analysts and traders said. The shares have fallen 4.3 percent since the raid.

Colombia is a key trading partner with Venezuela and Ecuador, supplying both with food and other goods.

Other companies that operate in Venezuela include Cementos Argos SA, Colombia's biggest cement maker, and Compania Colombiana de Inversiones SA, an investment holding company, Rupert Stebbings, head of international sales at brokerage Interbolsa, said by phone from Medellin.

``If push comes to shove, and Chavez is able to somehow reduce Colombian exports to Venezuela, Colombia takes a hit,'' said Boris Segura, an economist at Morgan Stanley in New York. ``A lot of Colombia's exports to Venezuela are industrial goods, which have high value added, and generate a lot of employment.''

Protesters and Chavez supporters gathered in the Plaza Venezuela near downtown Caracas today, carrying pictures of Uribe with a red handprint covering his face, and the words ``No More!''

In Bogota, a similar protest was held in Plaza Bolivar square, with participants carrying banners emblazoned with Chavez's image and chanting anti-Uribe slogans.