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Forces allied with Libya's unity government are closing in on Islamic State group fighters in Sirte in a month-long operation aimed at ousting the jihadists from their North African stronghold.
Here is some background on Sirte and its fall to IS.
Strategic importance
Sirte is on the Mediterranean coast roughly half way between Libya's capital Tripoli in the west and Benghazi in the east.
A major port city, it lies just 350 kilometres (220 miles) from the Italian coast.
It is also a mere 150 kilometres west of Libya's main oil-producing area and export terminals.
Oil is a vital source of income for Libya, and several groups have fought to control its wells and pipelines since the fall of Moamer Kadhafi in 2011. The IS presence in Sirte had raised fears it would attempt to seize the fields to fund its North Africa operations.
Population
Sirte used to have around 120,000 residents, most of them in the city centre or spread along the coast.
All but around 30,000 have fled since IS took over in June last year, a spokesman for pro-government forces, Reda Issa, told AFP.
Most people in Sirte belong to three major tribes including the Kadhadfa tribe of Kadhafi.
Infrastructure
Sirte has a large port, an international airport and an important military base. It also hosts one of North Africa's largest conference venues, the Ouagadougou conference centre which IS militants have been using as a command centre.
Kadhafi era
The home town of the former dictator, Sirte had a privileged position in Libya during his four-decade rule, not least because many residents belonged to the Kadhadfa tribe.
Post-Kadhafi
Sirte suffered major damage during the 2011 uprising.
Kadhafi loyalists used the city as a base to attack rebels in both the west and the east.
The dictator himself fled there after Tripoli fell to rebels at the end of August 2011. After Sirte also fell, gunmen tracked him down and killed him.
Sirte paid the price for supporting the regime. Heavy fighting destroyed entire streets. Residents accuse post-Kadhafi authorities of marginalising them in revenge for the dictator's rule.
Jihadist takeover
IS announced on June 9 last year it had captured Sirte. It has used it as a rear base, training foreign fighters to carry out operations overseas.
It hung its flags along the main streets, forced people to pray five times a day and banned women from leaving home without a male chaperone.
The group ruled Sirte through fear, brutally punishing dissent.
In May, Human Rights Watch said IS had beheaded or shot at least 49 people in Sirte for alleged crimes including blasphemy, sorcery and spying.
Forces loyal to the UN-backed Government of National Accord have been closing in on IS in the city since the operation began in mid-May.
IS forces are holed up in a dense residential district near the city centre, suggesting that the battle has become a street fight that could devastate the city even further.
W.Odermatt--NZN