SANAA, Yemen—Al-Qaida gunmen shot dead four soldiers Wednesday in one of the militants’ former south Yemen strongholds, officials said, as the local governor declared that the country’s ill-equipped police force is incapable of filling the security void left by months of clashes.

The militants staged a bold pre-dawn attack on a security building in Jaar, one of several cities in the south that they captured in 2011 while taking advantage of a popular uprising in the impoverished Arabian Peninsula nation. Witnesses said men stormed the building with automatic rifles. The officials spoke on condition of anonymity in line with regulations.

The army recaptured Jaar in June after a two month offensive backed by U.S. advisers, but many militants fled to nearby mountains and continue to launch attacks there and elsewhere in Abyan province. Wednesday’s attack came as the Defense Ministry announced it was redeploying thousands of troops to the south to prevent al-Qaida from retaking lost territory.

“The redeployment of the military to the cities here is to fill the security void left by the Interior Ministry who lack weapons and manpower,” Gov. Gamal al-Aqel told The Associated Press. “This leaves a lot of room for the possibility of al-Qaida’s return to the cities.”

Yemen’s ongoing power struggle also undercuts the security forces’ capabilities. The day before the attack, the headquarters of the Interior Ministry, which manages the police, was ransacked in the capital Sanaa in a bloody takeover by policemen loyal to the country’s ousted leader Ali Abdullah Saleh, who stepped down six months ago.

At least 15 people were killed and 43 wounded in the attack, officials said.

The incident points to the enduring ability of Saleh’s supporters, many of whom still hold key positions, to cause unrest in Yemen.

The police who stormed the ministry had accused the government of corruption, but Interior Minister Abdul-Qader Qahtan said Wednesday that the violence aimed to undermine the U.S.- and Gulf-backed initiative to ease Saleh out of power and reduce instability in the country.

“It’s a desperate attempt to delay the political process and the implementation of the Gulf initiative,” he said, referring to the power-transfer agreement that Saleh was pressured to sign after a year of protests against his rule.

According to the deal, Saleh handed over powers to his deputy in exchange for immunity from prosecution.

The ousted leader issued a statement Wednesday through the former ruling party, which he continues to head, denying that he had any role in the incident.

“We wish for a legal solution to the problem and respect for rights to avoid more bloodshed and to stop the political divisions inside the military and police,” the statement said.