At least seven people have been killed and 85 injured in flash flooding in Yemen this month, the UN said Tuesday, as the coronavirus threat also looms over the war-torn nation.

Yemen announced its first case of COVID-19 on April 10, and aid organisations have warned that its health system - all but collapsed since a conflict between the government and Huthi rebels broke out in 2014 - is ill equipped to handle the crisis.

"Heavy rains and flooding across northern governorates, including Marib, in mid-April led to casualties and damaged property and sites for internally displaced persons," the UN humanitarian coordination agency OCHA said.

"Initial information indicated that seven people - five women and two children - were killed in the flooding and another 85 people were injured, including seven who were seriously injured and hospitalised." The rebel-held capital Sanaa and districts in the same governorate "have been badly affected", it added. Storms also hit other provinces, including Ibb, Hajjah and Marib - which is the government's last northern stronghold and currently the conflict's "centre of gravity".