CAIRO (Reuters) - About 11,000 people have crossed from Ethiopia to Sudan fleeing the conflict in their home country and an estimated 50% of them are children, a U.N. refugee agency official said on Thursday. “They are coming with very, very little possessions and while most of them have actually come in in a healthy condition, we have had information on some who have been injured,” UNHCR representative Axel Bisschop told reporters in a virtual briefing. The agency had built a response plan for about 20,000 people, Bisschop said.“We also have a further contingency for up to 100,000 people but ... it’s too early to have an informed estimate of the amount of people who can actually arrive.” About 7,000 of those crossing have arrived at Hamdayat in Sudan’s Kassala state, with another 4,000 arriving at Luqdi in al-Qadarif state. Most of them are Tigrayan and some 45% of them are female, said Bisschop. One photograph of a border crossing point showed about four boats ferrying people across a river, he said.UNHCR and local authorities have identified one site 70-100 km (43-62 miles) from the border at which to host the influx of refugees and were working to identify others, he added. Ethiopia’s military has been waging a campaign against local forces in the northern Tigray region, where air strikes and ground combat have left hundreds dead.