Sana'a, Yemen  - Three powerful explosions shook three police buildings late Tuesday in the southern Yemeni city of Zunjubar, but no casualties were reported.

Witnesses told Deutsche Presse-Agentur dpa that two explosions were heard outside the compound of the Central Police force in the city, about 60 kilometres east of the southern port city of Aden.

The third blast hit the headquarters of the Criminal Police agency, they said, adding that the blast might have been the result of projectiles fired at the buildings.

A local journalist at the scene said that ambulances rushed to the scene of the third blast, but no confirmed reports on casualties were immediately available.

Zunjubar is near Ja'ar city, the stronghold of Jihadi groups in Yemen, which sits on the southern tip of the Arabian peninsula.

On August 30, police arrested Khaled Abdulnabi, a leading figure in the Islamic Jihad movement in Ja'ar, amid a clampdown on militant groups.

Security forces have since been pursuing five militants connected to bombings that targeted local government and police buildings in Abyan.

Police in Abyan have arrested 40 militants in a clampdown on militant groups last month in the rugged mountainous area of Hatat near Ja'ar. (dpa)