Kosovo closed its biggest border crossing on Wednesday after protesters blocked it on the Serbian side to support their ethnic kin in Kosovo in refusing to recognise the country’s independence. With two other crossings on the Serbian border closed by similar protests on their Kosovar sides since Dec. 10, only three entry points between the two countries remain open. The latest protest came hours after Serbia said it had put its army on the highest level of alert following weeks of escalating tensions between Belgrade and Pristina. Serbs in Serbia used a truck and tractors on Tuesday to create the latest roadblock, close to the Merdare crossing on Kosovo’s eastern border, Belgrade-based media reported. The obstruction is preventing thousands of Kosovars who work elsewhere in Europe from returning home for holidays. Around 50,000 Serbs living in ethnically divided northern Kosovo refuse to recognize the government in Pristina or the status of Kosovo as a country separate from Serbia. They have the support of many Serbs in Serbia and its government. “If you have already entered Serbia then you have to use other border crossings … or go through North Macedonia,” Kosovo’s Foreign Ministry said on its Facebook page, announcing closure of the Merdare crossing. The closure took effect at midnight, though the crossing was apparently already unusable. The Merdare entry point is Kosovo’s most important for road freight. The country has international rail links. Since Dec. 10, Serbs in northern Kosovo have exchanged fire with police and erected more than 10 roadblocks in and around Mitrovica. Their action followed the arrest of a former Serb policeman for allegedly assaulting serving police officers. On Tuesday, two more roadblocks were erected in the north. Albanian-majority Kosovo declared independence from Serbia in 2008 with the backing of the West, following a 1998-99 war in which NATO intervened to protect ethnic Albanian citizens. The government in Pristina has asked NATO’s peacekeeping force for the country, KFOR, to clear the barricades. But KFOR has no authority to act on Serbian soil.