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HERAT, Afghanistan, Sept 22 (Reuters) - Taliban insurgents have abducted more than 140 labourers involved in the construction of a military base in Afghanistan's western province of Farah, the provincial governor said on Monday.

They were seized by suspected militants on Sunday while travelling in three buses on a road in Bala Boluk district of Farah, governor Rohul Amin told Reuters. He added that authorities were trying to negotiate their release.

Both Taliban and criminal gangs are active in the area.

"Negotiations are under way by elders to release the innocent workers. We want to solve this issue peacefully without involving the military," Amin said.

A Taliban spokesman said he was not aware of the report of abduction by the militants.

A village elder who is involved in the negotiations said a powerful Taliban commander in the area was behind the abductions.

Apart from the Taliban, who are leading an insurgency against the Western-backed government in Kabul and foreign troops, criminal gangs have also been behind a series of abductions of foreigners and Afghans in recent years.

Kidnapping has become a lucrative business in Afghanistan, amid rising violence in the last few years.

In a separate incident, five Afghan guards from a local road construction company were killed in a Taliban attack in southeastern Paktia province on Monday, an official from the region said.

Six civilians, including one child, were killed and four wounded in a third incident when their vehicle struck a roadside bomb in the southern Uruzgan province on Monday, NATO said.

The district commissioner and district police chief of Registan district in Kandahar province along with two policemen were killed in a landmine explosion, officials said on Monday.

Violence has surged to its worst level in Afghanistan this year, the bloodiest period since U.S.-led troops overthrew the Taliban government in 2001.

Despite an increase in strength of foreign troops, now numbering more than 71,000, the al Qaeda-backed Taliban have intensified attacks and extended the scope of their activities. (Reporting by Sharafuddin Sharafyar in Herat and Saeed Ali Achakzai in Kandahar; Writing by Hamid Shalizi; Editing by Keith Weir)

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