A Kenyan air strike killed five people, including children, in Jibil food distribution camp in southern Somalia last Sunday, according to Médecins san Frontières.
The Kenyan military denies responsibility.
Kenya has closed its border, preventing refugees from crossing.
Kenyan troops entered Somalia in mid-October. The government claimed it was pursuing the Islamist Al Shabaab militia, who it blamed for a spate of kidnappings. It produced no evidence to support this.
The raid has now become a full-scale invasion, backed by the US, in an extension of the “war on terror”. Kenya is calling for international “logistical and financial support” to eradicate the militia.