Kosovo today closed its biggest border crossing after protesters blocked it on the Serbian side to support their ethnic k<br />''<span style="color: #222222;">in Kosovo in refusing to recognize the country's independence. <br />''<br />''The latest protest came hours after Serbia said that it had put its army on the highest level of alert following weeks of escalating tensions between Belgrade and Pristina. <br />''<br />''Serbs in Serbia used trucks and tractors yesterday to create the latest roadblock, close to the Merdare crossing on Kosovo's eastern border. The obstruction is preventing thousands of Kosovars who work elsewhere in Europe from returning home for holidays.</span><br />