Authorities have interrogated a person suspected of throwing the explosive device out of a moving car, police spokesman Ljudevit Maric said on Saturday.

No one was injured in the incident, with the car carrying General Anto Jelec passing safely through the tunnel near the southern town of Mostar late Friday, officials claim.

The blast was most likely caused by a pyrotechnic device, prosecutor Maja Cisic said, citing preliminary information.

"According to the facts we have so far, I do not believe this was an attack on the General Anto Jelec, but I cannot state anything with full certainty before the end of the investigation," she added.

The blast caused only minor damage to the road and the authorities have cleared the tunnel for traffic.

Terror threat

Security forces in Bosnia are on edge following a deadly terror attack earlier in the week. Then a suspected Islamist gunman killed two Bosnian soldiers and fired at a bus with an assault rifle.

The gunman killed himself after police surrounded his home at the outskirts of Sarajevo.

Most Bosniaks are moderate Muslims, although a small percentage have embraced more conservative interpretations of Islam after the bloody Bosnian war two decades ago.

Islamist groups from abroad supported Bosnian troops against both Serbian and Croatian forces during the 1992-95 conflict.

dj/jm (Reuters, FENA, Beta)