United Nations, March 4 : Twenty-two truckloads of aid from the World Food Programme and the UN Children's Fund (Unicef) crossed into Northwest Syria from Turkey, bringing the total of cross-border delivery to 557 trucks since February 9 in the wake of massive earthquakes, said a UN spokesman. The UN has carried out 18 inter-agency cross-border missions to Northwest Syria since the first interagency visit to Idlib on February 14, said Farhan Haq, deputy spokesman for UN Secretary-General Antonio Guterres, at a daily press briefing on Friday. On Thursday, a joint delegation by the UN Office for the Coordination of Humanitarian Affairs and Unicef carried out a mission focussed on gender and accountability to affected people, including a field visit to a site for internally displaced persons in Kelly Mountain and to Al-Iman hospital in Sarmada, Idlib, he added. "Our humanitarian colleagues also tell us that over 105,000 households have reportedly been displaced following the earthquakes. Many are staying with host communities or going back to their inhabitable homes, making it very difficult to estimate the total number of displaced," said Haq as quoted by Xinhua news agency report. The world body is currently supporting structural damage assessments of affected buildings to help facilitate families' return. Longer-term shelter operations are also being identified for families that cannot return to their homes due to the scope of the damage, he added. The $400-million appeal in response to the February 6 earthquakes has so far received $173 million, or 43.5 per cent of the funding required, he said. /IANS