The USD/JPY pair dropped sharply from session tops and hit fresh daily lows after Brexit jitters returned to markets as the Britain headed for the EU referendum.USD/JPY changes course as polling gets underwayThe US dollar gave back its previous advance against the Japanese yen after the UK polling began, as investors turned cautious about the referendum outcome and therefore, turned to the safe-haven yen. At the time of writing, USD/JPY trades almost unchanged at 104.38, recovering from 104.14 session lows, having previously faded a spike to 104.75.While the US dollar remains in the red against its major peers, largely impacted by Brexit –driven GBP moves. The USD index now drops -0.27% to 93.55 levels. Next of note remains the US unemployment claims and new home sales data for fresh incentives on the buck.USD/JPY Technical levels to watchIn terms of technicals , the immediate resistance is located at 104.94/98 (10-DMA/ daily top). A break above the last, the major could test 105.31/50 (daily R2). While to the downside, the immediate support is seen at 104 (round number) and below that at 103.56 (multi-month low).