Ethiopian troops have crossed the border into Somalia in significant numbers, eyewitnesses say.
They say they saw at least 20 vehicles carrying Ethiopian troops.
A few hundred soldiers were seen in Gurel town in Galgudud region and there were other sightings around Beledweyne.
Ethiopian authorities have denied the incursion. Their soldiers have not been in Somalia in large numbers since 2009 when they withdrew after a controversial three-year presence.
These reports come as Kenyan troops continue their efforts to defeat fighters of the Islamist group al-Shabab in the south of Somalia.