Islamabad, Nov 23 : At least 18 people have been killed and over 30 others injured in armed clashes between two groups in Pakistan's northwest Khyber Pakhtunkhwa province, officials said on Saturday.

The clashes erupted in Kurram district of the province, where armed men killed dozens of people and torched shops, houses and government property, the official sources said on condition of anonymity.

The sources added that the latest violence in Kurram district was linked to Thursday's attack, in which unidentified gunmen attacked a convoy of passenger coaches carrying Shiite Muslims, killing 45 people and injuring at least 16 others.

In response to the ongoing violence, the local administration has imposed a curfew in the area, closed educational institutions and businesses and suspended cellular services.

Kurram Deputy Commissioner Javedullah Mehsud told media that efforts were being made to restore peace in the area, saying an emergency meeting has been held to prevent further violence, Xinhua news agency reported.

Kurram district has a history of sectarian violence. In September, at least 60 people from both sects were killed in separate incidents, according to Provincial Governor Faisal Karim Kundi.

The situation had remained extremely tense in the region since Thursday as Iran-backed Zainebiyoun Brigade vowed to avenge the killing of 45 Shia Muslims by unidentified gunmen.

The Shia-dominated Parachinar area, which has seen bloody confrontational clashes with the surrounding areas of the Sunni majority in the past, saw police vehicles and security checkpoints being set ablaze as roads were blocked by stones and burning tyres.

The protesters in Parachinar also demanded immediate opening of the border with Afghanistan amid worsening situation, shortage of food, medicines, fuel and oxygen.

A Shia organisation and political party Majis Wahdat Muslimeen (MWM) has put forward demands to the government, including activating the Parachinar airport due to unsafe roads and the starting of free shuttle service between Parachinar and Peshawar via PIA or air force planes.

MWM has also called for replacement of federal forces by local Kurram militia.

The protestors have warned if their demands are ignored by the provincial and federal government then they would be forced to seek international help by human rights organisations and even the United Nations.

/IANS