US credit calms markets in an uncertain Mexico: Party militants jeer presidential rival at Colosio wake, writes Phil Davison in Mexico City

AN emergency credit line of dollars 6bn ( pounds 4bn) from the US, and the news that Mexico would become the first Latin American member of the Organisation for Economic Co-operation and Development, helped to calm the nation yesterday in the wake of the assassination of the ruling party's presidential candidate.

Life returned to normal after a day of mourning on Thursday, but there was an air of uncertainty five months before the scheduled presidential elections.

While the assassination of 44- year-old Luis Donaldo Colosio came as a shock, most Mexicans took it in their stride. The killing plunged Mexico into its worst political crisis since the 1920s. Colosio, though amiable and considered honest by his party's standards, could hardly have been described as popular outside his party's supporters, but among militants of the Institutional Revolutionary Party (PRI) emotions were running high.

Colosio's rival for the PRI's presidential candidacy, Manuel Camacho Solis, was booed, and called 'hypocrite' and even 'assassin' when he attended a wake for Colosio on Thursday evening. Mr Camacho had expressed disappointment when his old friend, President Salinas de Gortari, chose Colosio as PRI candidate last November.

Mr Camacho was appointed government negotiator with the Zapatista guerrillas in the southern state of Chiapas after an armed uprising there in January. That task gave him a much higher profile and led many to believe Mr Camacho hoped to oust Colosio as candidate. Mr Camacho reiterated yesterday that he did not want the presidency. The assassination, in the light of his rivalry with Colosio, appeared to have reduced his chances of being named as the substitute candidate.

Colosio's body was taken in a cortege to Mexico City airport for burial in his home village of Magdalena de Kino, near the US border.

His confessed killer, Mario Aburto Martinez, 23, who shot Colosio in the head and stomach on Wednesday evening in the border city of Tijuana, was being held in a maximum security jail outside Toluca, near here. Television film footage showed Mr Martinez, his shirt ripped off, being battered by the crowd as police tried to rush him from the scene.

Justice officials who interrogated him said he had confessed. They described him as 'very sure of himself, confident'. US officials revealed that the Brazilian-made Taurus .38-calibre pistol he allegedly used to fire two bullets at Colosio had first been bought in San Francisco in 1977. Investigators were looking into reports by neighbours that Mr Martinez had recently been visited by a group of young men from the US.

Mexico's trade union confederation chief, Fidel Velazquez, yesterday voiced widespread suspicion that the New Year Zapatista rebellion and Colosio's assassination may have been linked, even though the two events took place at opposite ends of the country.

The Zapatistas timed their uprising to coincide with the day the North American Free Trade Agreement (Nafta) with the US and Canada came into effect. In Chiapas, many believed US opponents of Nafta had armed or supported the Indian peasant guerrillas.

Mexico's Senate approved constitutional amendments that will end the PRI's long grip on electoral institutions. The move was a direct result of the Zapatistas' demands for greater democracy in a country where the PRI has ruled supreme for 65 years, only in recent years allowing opposition parties to make inroads to satisfy the outside world.

The stockmarket reopened 79 points, or around 3 per cent, down yesterday after Thursday's day of mourning.

President Bill Clinton's announcement of a dollars 6bn 'swap facility' to ensure Mexico has enough dollars to avert a possible run on the peso, was seen as preventing a worse market crash. So, too, was Mr Salinas' announcement that Mexico would be the first new member of the OECD for more than 20 years - since New Zealand was admitted in 1973.