1325 GMT - Global markets could face increased volatility due to rising geopolitical tensions, uncertainty around the U.S. midterm elections and an unclear outlook on U.S. interest rates, Validus Risk Management's Kambiz Kazemi says in a note. Renewed U.S.-Iran hostilities have caused oil prices to rise and weakened risk appetite. "Monetary policy uncertainty, political risk and geopolitical tension" could drive volatility across asset classes, he says. Ten-year gilt yields rise 1.9 basis points to last trade at 5.158% and ten-year Bund yields climb 2.8 basis points to 3.369%, Tradeweb data show.