SANAA: Yemen offered a $25,000 reward on Thursday for help in catching the killers of a Saudi Arabian diplomat, a day after he was gunned down in an attack that security authorities blamed on al Qaeda.

The killing on Wednesday of Khaled al-Enizi, a military attache at the Saudi embassy, and his Yemeni bodyguard underscored the challenges facing the U.S.-allied state since an uprising last year that ousted president Ali Abdullah Saleh.

A Yemeni security committee offered a reward of 5 million rials ($25,000) for any information leading to the killers, state news agency Saba said.

Dressed as security officers, the attackers blocked a car carrying Enizi, an aide to the Saudi military attache, and opened fire, the security committee said in a statement. The diplomat and his guard died instantly.

No one has claimed responsibility for the attack which took place near the diplomat's house in the capital but a Yemeni security official said on Wednesday authorities were "assuming that al Qaeda was behind it".

In a separate incident, armed men seized Nameeri al-Awadi, head of traffic police in al-Kotn town in Hadramout province, on his way back home after the dawn prayer, a local official said. No one has claimed responsibility for the kidnapping but the official said he believed al Qaeda militants were behind it.

Yemen-based Al Qaeda in the Arabian Peninsula (AQAP), regarded as al Qaeda's strongest regional wing, has mounted operations in Saudi Arabia and tried to launch attacks against the United States.

Restoring stability in Yemen is a priority for Washington and its Gulf allies because of its strategic position next to top oil exporter Saudi Arabia and major shipping lanes.

"The threats are always there and they usually come from al Qaeda in Yemen," Saudi Arabia's ambassador to Yemen Ali al-Hamdan told the Saudi-owned Asharq al-Awsat newspaper.

The Saudis are a major donor to their poor neighbour and hosted the signing of a power transfer deal under which President Abd-Rabbu Mansour Hadi took over as head of state in February after Saleh stepped down.

Islamists linked to al Qaeda kidnapped a Saudi deputy consul in the southern city of Aden in March and are still holding him. They have demanded a ransom and the release of women prisoners, believed to be relatives of al Qaeda fighters.