More than 20 senior European foreign affairs politicians have called on Commission President Ursula von der Leyen to investigate allegations of fraud in December’s election in Serbia. “We call on the EU to conduct an independent investigation of all reported election irregularities and claims of fraud,” the politicians wrote in a letter seen by POLITICO and addressed to the bloc’s top brass, including von der Leyen, European Council President Charles Michel and European Parliament President Roberta Metsola. Serbia’s illiberal President Aleksandar Vučić tightened his grip on power by claiming victory in the December ballot, sending tens of thousands of people into the streets of Belgrade to protest what they claimed was a stolen election.  The 24 signatories of the letter, including Michael Roth, chairman of the Foreign Affairs Committee of the German parliament, and his French counterpart Jean-Louis Bourlanges, called on the EU to investigate the fraud allegations independently and to make recommendations to ensure free and fair elections in Serbia.  The signatories mostly chair the foreign or European affairs committees in their national parliaments and come from …