According to reports, the Ethiopian air force struck the town of Togoga on Tuesday, 25 km (15 miles) from the region’s capital, Mekelle.
Although this has been denied by the Ethiopian government, thousands of people have been killed and millions displaced after conflict erupted almost eight months ago.
Doctors at the main hospital in Mekelle say they are treating dozens of people including a two-year-old child left injured by the airstrike.
Medical personnel told the press that the Ethiopian military blocked them from reaching the site of the attack to help others left behind.
Ethiopia’s army said the strikes were against military targets. “We never carried out an airstrike on the marketplace. How is this possible? The army is capable of accurately hitting its targets. We conducted airstrikes, but only on certain targets,” a spokeswoman said.
The TPLF had had a massive fallout with Prime Minister Abiy Ahmed over his political reforms though its capture of federal military bases in Tigray was the catalyst for the invasion.
The TPLF has since joined forces with other groups in the region to form the Tigray Defence Force (TDF) rebel group.
Speaking to the press on Monday after casting his vote in the twice-delayed national election, Mr Abiy said he was working with the troops in neighbouring Eritrea to get them to leave but said he would not “push them out”.
They are accused of carrying out massacres, mass rape and blocking humanitarian aid – charges Eritrea has denied.