* Gas pipeline, hit by Nigeria strike, poses risk to GDP (Adds central bank concern over gas pipeline)

TUNIS (Reuters) - Tunisian police killed an Islamist militant during clashes near the Algerian border, the interior ministry said on Wednesday, after the government raised the security alert level before elections next month.

BAMAKO (Reuters) - At least 16 people were killed following the collapse of a shaft in an artisanal gold mine some 130 kilometres (80 miles) south of Mali's capital Bamako, the West African state's mines ministry said late on Tuesday.

BAMAKO, Sept 17 (Reuters) - At least 16 people were killed following the collapse of a shaft in an artisanal gold mine some 130 kilometres (80 miles) south of Mali's capital Bamako, the West African state's mines ministry said late on Tuesday.

JOHANNESBURG (Reuters) - As many as 300 South Africans were visiting a Pentecostal church in Nigeria last week when a building in the compound collapsed, killing more than 60 people, and an unknown number are still unaccounted for, the government said on Wednesday.

BENGHAZI Libya (Reuters) - Heavy clashes broke out on Tuesday between a former Libyan general's forces and Islamist fighters in the eastern city of Benghazi, killing at least nine people, medics said.

LAGOS (Reuters) - Nigerian oil workers said they had started a strike on Tuesday that may affect exports, although market sources doubted they would have an impact and similar strikes in recent years have not significantly hurt production or exports.

ATLANTA/MONROVIA (Reuters) - President Barack Obama on Tuesday called West Africa's deadly Ebola outbreak a looming threat to global security and announced a major expansion of the U.S. role in trying to halt its spread, including deployment of 3,000 troops to the region.

NAIROBI, Sept 17 (Reuters) - The following company announcements, scheduled economic indicators, debt and currency market moves and political events may affect African markets on Wednesday. - - - - - EVENTS: GHANA - Bank of Ghana's Monetary Policy Committee (MPC) announces policy rate decicion. Kenya - Central Bank auctions 182-day and 364-day Treasury bills worht a total 8 billion shillings ($89.99 million). GLOBAL MARKETS Asian shares were tentatively higher on Wednesday after W