CAIRO (AP) — A roadside bombing in Egypt's restive northern Sinai killed at least four troops on Thursday, military and security officials said, adding that the attack was carried out by militants in the region.

The bomb went off when an armored military vehicle was combing an area around the border village of el-Mahdiya, close to the town of Rafah, which borders Gaza Strip, according to the Egyptian military spokesman, Brig. Gen. Mohammed Samir.

In a statement on his official Facebook page, Samir said the explosion killed one officer and three soldiers and also wounded three troops.

However, a security official in Sinai said the explosion occurred outside a checkpoint near el-Mahdiya, killing the four troops who were inside an armored vehicle. Clashes with militants then ensued, killing a fifth soldier, said the official, who spoke on condition of anonymity because he was not authorized to speak to reporters.

The official also said that at the same time, militants clashed with troops at two separate checkpoints in other parts of northern Sinai, wounding four soldiers. A military official denied the two separate clashes.

It was not immediately possible to reconcile the different accounts. Media access to northern Sinai, where military operations have intensified since 2013, is limited.

Egypt is battling a widening insurgency that has largely targeted troops in northern Sinai. Recently, the attacks have expanded to reach the capital of Cairo, with a car bombing killing the country's chief prosecutor in late June and another striking outside the Italian Consulate earlier this month. The militants say they are avenging a government crackdown on Islamists.