Three people were killed and five others injured on Thursday when gunmen stormed the National Bank's branch in Yemen's southern port city of Aden, according to provincial officials.

Eight masked militants attacked the bank, with the first four breaking into the building and the other four shooting randomly, a source close to the province's police chief said.

"All eight attackers escaped. Three of the bank's security guards were killed while workers were evacuated to a safe place," he added.

The manager of the government-owned National Bank refused to open the safe and was critically injured in the armed robbery attack, one of the bank workers told Xinhua.

No group immediately claimed responsibility for the armed robbery attack. But al-Qaida gunmen and other terrorist groups have recently increased their attacks against Yemeni security forces across the country.

The southern port city of Aden is the headquarters of Yemen's internationally-backed President Abdu-Rabbu Mansour Hadi and his government.

Aden witnessed several well-planned assassinations and armed attacks after Saudi-backed forces drove the Shiite Houthi rebels out from the strategic city in July 2015.

Security in Yemen has deteriorated since March 2015, when war broke out between the Shiite Houthi group, supported by former President Ali Abdullah Saleh, and government forces backed by a Saudi-led Arab coalition.

source: xinhua