A Somerville man pleaded not guilty Tuesday to charges of beating an unarmed US Army veteran who was wounded in the Iraq war, the Suffolk district attorney’s office said. James Plunkett, 26, pleaded not guilty to charges of assault and battery and of assault and battery with a dangerous weapon, a shod foot, at his arraignment in Boston Municipal Court, District Attorney Daniel F. Conley’s office said. Plunkett and another man were urinating near the corner of Charles and Pinckney streets around 1:30 a.m. Monday when the 29-year-old veteran asked the men to “put it away” so he and his wife could pass by, prosecutors said. An argument ensued, and the two men allegedly followed the couple to their car. Plunkett and the other man threw several punches at the victim, according to prosecutors, then allegedly continued to punch and kick him after he fell to the ground, the district attorney’s office said. The veteran was taken to Massachusetts General Hospital where he was treated for a broken nose, a broken bone in his hand, and facial injuries. His wife was not injured. The second assailant has been identified by Boston police and may be charged at a later date, prosecutors said. Plunkett’s bail was set at $1,000, and he was ordered to have no contact with the victim. He is scheduled to return to court Dec. 4.