Spain's Juan Yanez, after previous meetings this week with Argentine officials, held talks with a top aide to President Tabare Vazquez and foreign ministry representatives.

Uruguay's government did not comment on the meeting, which was seen as an attempt by Yanez to get the countries talking again after months of bitter wrangling over the pulp plant, Uruguay's most ambitious foreign investment initiative in history.

The Finnish consortium Oy Metsa-Botnia AB and Kymmene Corp. has earmarked $1.2 billion (euro920 million) to complete the plant, which would create hundreds of jobs and is reported to be nearly 80 percent complete.

But Argentines claim the sprawling pulp mill rising near Fray Bentos, Uruguay, will cause lasting environmental damage by polluting the Uruguay River and surrounding farmlands and citrus plantations. They demand the project be abandoned. Uruguay argues its studies show any pollutants will be within international limits.

On Wednesday, Argentine environmental protesters closed the crossing at Concordia, Argentina, one of the only routes that had usually remained open during nearly a year of sporadic blockades at two crossings further downstream.

This left all three bridge routes between the countries blocked as vacationers traveled to and from Uruguay's beach resorts during the southern hemisphere summer.

Protesters said they were emboldened to step up blockades after the International Court of Justice on Jan. 23 refused Uruguay's plea to order the barricades dismantled.

One crossing at Gualeguaychu, Argentina, has been blocked continuously for two months, and another crossing at nearby Colon, Argentina, frequently has been blocked.

Uruguay claims the protests have cost it more than US$200 million (euro154 million) in lost commerce since late 2005. Thousands of Uruguayans have rallied in support of the mill and Vazquez has said he will allow the plant to be completed.