RIYADH—The European Union foreign policy chief said on Sunday the Taliban government’s behavior up to now was “not very encouraging”, and any economic collapse in Afghanistan would raise the risk of terrorism and other threats. Josep Borrell, speaking at a joint news conference with his Saudi Arabian counterpart, also said he hoped nuclear talks between global powers and Iran would restart in Vienna “soon”. The EU diplomat, who is in Riyadh following visits to Qatar and the United Arab Emirates, said he briefed his partners on the prospects for restarting nuclear talks and exchanged views with Saudi officials on Yemen and Afghanistan. The EU has increased its humanitarian aid to Afghanistan since the Taliban took power, but halted development assistance—a move also taken by other countries and the World Bank. “Certainly it’s a dilemma. Because if you want to contribute to avoid the collapse of an economy, in a certain …