Brazilian government officials said Wednesday that they would crack down on cattle ranchers in the Amazon after new data showed that deforestation there had increased by 26 percent in the nine months that ended in April, compared to with the same period a year before. The data showed to that about 710 square miles had been deforested in that time. Izabella Teixeira, Brazil’s environment minister, called the jump “unacceptable” and vowed to seize the cattle of farmers who are practicing deforestation to cultivate new pastureland. Ibama, Brazil’s environmental protection agency, more than doubled police operations this year intended to deter deforestation. Despite those efforts, Mato Grosso, Brazil’s leading soybean-producing state, saw a 43 percent increase in deforestation in the nine-month period that ended in April, compared to with the same period last year. Leading environmentalists said some farmers had cut down trees because they expected they would be allowed to do so anyway under a bill being considered in Brazil’s Congress to ease restrictions on the amount of land that needed to remain forested.