Argentina's largest farm groups promised Friday to end their third strike in three months at the request of the Roman Catholic Church, but warned they'd continue on "alert" until the government repeals new export taxes on grains. The strike, during which farmers suspended grain exports and blocked major highways, will be lifted at midnight on Sunday - although farmers will continue roadside protests where they "consider it necessary," the country's four largest farm groups said in a news release. Argentina's Catholic Bishops' Conference this week asked farmers to abandon their strike in a "gesture of magnanimity" to preserve social peace. They also asked President Cristina Fernandez to convene talks with farmers over the disputed export tax hike. Farmers have held three separate strikes since Fernandez decreed an increase in grain export taxes on March 11. The longest strike was in March, when they suspended shipment of farm products for 21 days, causing scattered food shortages. The farm strikes mark the first political crisis for Argentina's new president, whose approval ratings have plummeted in recent weeks.