A suicide bomber blew himself up outside a sufi shrine in Pakistan's restive southwest Thursday, killing 13 people and wounding at least 20 others, officials said.

The incident took place in the Gandawa area of Jhal Magsi district in the oil and gas rich Balochistan province, bordering Iran and Afghanistan.

"A suicide bomber blew himself up after he was intercepted by police guards on duty outside the shrine, killing 13 people and wounding at least 20 others," senior local administration official Asad Kakar told AFP.