By Tyler Clifford NEW YORK (Reuters) – The New York Police Department has called for “elevated vigilance” ahead of the U.S. midterm elections, warning that extremists could target political events and polling sites, according to media reports. Poll workers, people at rallies and political candidates face heightened risk of attack in the run-up to the Nov. 8 elections, according to an internal bulletin that was issued by the department on Wednesday and obtained by ABC and CNN. The bulletin stressed it was drawing attention to the risk of attacks or threats even though there were no credible thr…