TUNIS — At least 14 Tunisian soldiers were killed on Wednesday, July 16, when gunmen with rocket-propelled grenades attacked two checkpoints in the remote Chaambi mountains, the deadliest militant strike on the north African country’s armed forces.

Since April, thousands of Tunisian soldiers have been deployed to the Chaambi range bordering Algeria in an operation to flush out al-Qaeda-linked militants seeking refuge there, some since fleeing French intervention in Mali last year.

Militants ambushed the checkpoints at night, killing the soldiers as they were breaking their fast for the evening during the Muslim holy month of Ramadan, the Defense Ministry said. More than 20 soldiers were wounded.

“It was two simultaneous terrorist attacks when they were breaking their fast. Bodies of nine burned after they were hit with an RPG. Five more were shot,” said Col. Major Souhail Chmangi, chief of army land forces. “This is open warfare.”

Another soldier is missing after the attack, but authorities could not confirm if he had been kidnapped.

Tunisia’s stock market dropped 0.33 percent after the news of the deaths.

Tunisia has struggled with the rise of radical Islamist militants since the 2011 popular revolt ended the rule of autocrat Zine el-Abidine Ben Ali and began its fragile steps towards democracy.

Militants calling themselves Okba Ibn Nafaa Brigade claimed responsibility on a social media site. That claim could not be verified, but Tunisia says the group is operating in Chaambi and is tied to al-Qaeda’s North Africa wing.

Al-Qaeda in the Islamic Maghreb, the north Africa branch, has also claimed attacks in Tunisia in the past, but another militant group, Ansar al Sharia, listed as a terrorist organization by Washington, is also active.