US defense officials said Friday that Russian fighter jets flew into Ukrainian airspace a handful of times over the last 24 hours, in what one called a continued provocation of the heightened tensions in the region.  The officials said it’s not clear what the intent was, but the aircraft could have been testing Ukrainian radar or making a show of force. Col. Steve Warren, a Pentagon spokesman, confirmed the flights, adding that the U.S. is calling on the Russians “to take immediate steps to de-escalate the situation.” More