SANAA — Angry soldiers kidnapped a senior Yemeni officer on Thursday over a pay dispute, a local official said, raising fears over the unity of a fighting force the United States is counting on to help crush a tenacious offshoot of Al Qaeda.

A popular uprising last year triggered a string of defections from the army, dividing its ranks into pro- and anti-government camps that fought each other and dragged the impoverished state to the brink of civil war.

The abduction of Brigadier General Murad Al Awbali, commander of the 62nd Brigade of the Republican Guards, is likely to worry Washington. He was snatched while travelling east of the capital Sanaa, the official said.

The United States has urged Yemen's leaders to unify the army to ensure it presses ahead with a US-backed offensive against Islamist fighters in the south of a country that borders Saudi Arabia, the world's top oil exporter.

Awbali, a loyalist of ousted President Ali Abdullah Saleh, had stopped paying salaries to soldiers who had broken ranks with the former president and his son, Ahmed, who still heads the Republican Guard, the official said.

The soldiers had been ordered to return to the brigade to collect their salaries, the official added, but had refused to do so while Saleh's son, Ahmed, remained in charge for fear of disciplinary action.

Awbali himself had been implicated in a crackdown on anti-government protests in the city of Taiz last year.

A source in Saleh's General People's Congress party blamed "militias" loyal to the opposition Islamist Islah Party as well as the First Armoured Division — which mutinied in the early days of the revolt — for the kidnapping.

Earlier this month, the army drove militants from their strongholds in the south — territory they had seized when the country was convulsed by turmoil — but the assassination of a top southern military commander days later showed the threat from Al Qaeda-linked fighters had not receded.