Venezuelan President Nicolas Maduro has said that the Colombian government is backing an assassination plot against him as the two countries strive to get regional support amid a border crisis, Associated Press (AP) reported Monday.

The allegations were made during Maduro's visit to Vietnam and follow his earlier accusation that the Colombian government is trying to topple his government. Maduro said he will soon divulge further details. Officials in the Colombian capital of Bogota did not respond to the allegations.

Maduro’s comments came as diplomats from 34 Western Hemisphere countries gathered for an emergency meeting at the Organization of American States (OAS) in Washington to discuss the closure of six border crossings between Venezuela and Colombia, which has triggered a humanitarian crisis. However, Monday's proposal calling for foreign ministers of all 34 countries to discuss the border crisis failed to garner the necessary 18 votes and, the Colombian government said Monday, according to Reuters, that the OAS will not hold talks.

Last week, Maduro set a 72-hour deadline for nearly 500 migrant families to vacate their homes in a crackdown, which began after three gunmen attacked three Venezuelan soldiers in the western state of Táchira. Maduro claimed the attackers belonged to Colombian paramilitary groups and closed border crossings on Aug. 20.

An AP report said that about 10,000 Colombians, who were living in Venezuela illegally, have been forced to flee since then. While Maduro claimed that the crackdown against migrants is necessary to counter gangs, who buy gas and other goods at subsidized prices in his country and sell them abroad for significant profits, his move has attracted criticism.

Human rights groups, the U.S., United Nations and the European Union have countered Maduro’s reasoning and have contested his decision to declare emergency in several states, sending thousands of troops to the border. Maduro's officials have also closed 177 illegal border crossings, AP reported.