But observers say there is little doubt that it is the latest in a series of retaliatory measures by both countries since Colombia sparked a regional crisis with its brief incursion into Ecuadorean territory in March 2008 to kill a high-ranking leftist rebel leader.

Ecuador's move follows the unusual filing of murder charges last month by a local judge against former Colombian Defense Minister Juan Manuel Santos, who planned the incursion last year that left more than 20 people dead in addition to Raul Reyes, a leader of the Revolutionary Armed Forces of Colombia, or FARC.

The Ecuadorean government subsequently signaled its approval of the charges by requesting that Interpol issue a "red notice" for Santos to authorize his arrest by foreign countries. Interpol turned down the request last week, but Colombia signaled that it was offended by Ecuador's actions.

Last week, Colombian President Alvaro Uribe accused Ecuador of harboring terrorists. "This is nothing but a pirouette by abettors of a torturing, criminal, cynical and sadist group that is the FARC," he said, reacting to Ecuador's Interpol request.

Ecuador's president, Rafael Correa, responded by accusing Uribe of sponsoring right-wing paramilitary groups, also classified as terrorists by the U.S. State Department.

Colombia then struck back by filing a suit in the International Criminal Court accusing Correa, ex-Interior Minister Gustavo Larrea and ministry official Ignacio Chauvin of links with the FARC. Officials say evidence from laptops seized in Reyes' camp after the raid about a mile south of the Colombian border indicates that the FARC had extensive contact with Ecuadorean officials.



Rebel ties denied

Correa has rejected claims that Ecuador is rebel-friendly and although both Larrea and Chauvin acknowledged meeting with FARC operatives several times before the raid last year, they insisted it was for humanitarian purposes -- to secure the release of FARC hostages, including three U.S. defense contractors who were rescued in July 2008.

Chauvin is also being investigated for alleged links to drug traffickers.

In any case, Ecuador's foreign minister, Fander Falconi, said last week that relations between the two nations were at a low point. Analysts are concerned that the war of words and dueling lawsuits could escalate.

"They're playing with fire, these presidents who are as media-savvy as they are popular in their countries," said Socorro Ramirez, a professor at National University in Bogota, the Colombian capital. "They're creating a scenario for a dangerous skirmish that the international community should help avoid at all costs."

The raid by Colombian forces last year raised regional tensions and prompted both Ecuador and Venezuela to briefly mobilize troops along their borders with Colombia. At a Latin American summit shortly after the raid, Correa and Uribe shook hands, giving rise to hopes the matter was settled.



An apology sought

But Correa continues to condemn the raid as an outrageous violation of national sovereignty, a position supported by the Organization of American States, and claims Colombia has never given a full accounting or an apology for the incident.

Correa's ire has been fueled anew by Colombian Defense Minister Santos' statements in April that the operation to kill Reyes was justified

The two nations historically have had good relations, buttressed by trade, which neither country can afford to lose.

Ecuador is Colombia's third most important export destination after the United States and Venezuela. Colombia ships large quantities of rice, furniture, gasoline and medical products to Ecuador.

But Ecuador has demanded that Colombia take several measures to improve relations, including stationing more troops along their border to check the flow of armed groups, drugs and immigrants.

Ecuador also challenged Colombia to provide it with videotapes made by the aircraft that participated in the raid to prove that Colombian armed forces acted without U.S. assistance.

Ecuador has other grievances that predate the Reyes raid. It has filed a complaint with the international court in The Hague claiming that Colombia's spraying of defoliants to kill coca plants in the border area has hurt Ecuadoreans' economy and health.

Ecuador also claims that Colombia does little to impede the thousands of Colombian refugees who flow into Ecuador to escape their country's civil war.

**Kraul is a special correspondent.