20th Day of Argentine Farmers' Strike

BUENOS AIRES, Argentina -- Supporters of President Cristina Fernandez planned a mass rally on Tuesday to back the Argentine leader as she confronts a 20-day farm strike that is causing food shortages and disrupting grains exports.

As farmers continue to man roadblocks to protest a tax hike on soy exports, trade union and social groups allied with the center-left government will gather in front of the presidential palace in central Buenos Aires.

Local media said organizers were hoping to draw as many as 80,000 people. The march comes a week after thousands of middle-class Argentines banged pots and pans in the capital's streets in support of the farmers.

The strike, which began on March 13, has become the most serious political challenge faced by Fernandez, who took office in December succeeding her husband, former President Nestor Kirchner.

On Monday, Fernandez offered some concessions to farmers but ruled out doing away with a new sliding-scale tax scheme, which has been the farmers' main demand.

The government said it would give small farmers a rebate on new, higher taxes for soy and sunflower seed exports, plus compensation for transport costs for farmers who work far from ports.

But farm leaders said the measures did not go far enough and announced they would continue striking until Wednesday, at least.

"The [government] has given its response to the concerns submitted by the agricultural groups. There is no reason for the strike to continue," Interior Minister Florencio Randazzo told local radio.

The farmers are protesting the new tax system, which replaced a fixed levy of 35 percent on soybean exports with a variable rate that is about 40 percent at current prices.