MADRID (Reuters) - An al Qaeda cell based in France planned a chemical attack on a U.S. naval base in Rota, Spain, newspaper ABC reported on Tuesday. Algerian Said Arif, extradited to France from Syria last year, has admitted his cell was plotting a chemical attack on the southern Spanish base controlled by the United States since 1953, the Spanish daily reported. The paper said Arif was considered a lieutenant of Jordanian Abu Musab al-Zarqawi, al Qaeda's leader in Iraq. Zarqawi himself was accused of planning a chemical attack last year in his native Jordan, which authorities thwarted. Arif was...