Aug 24 (Reuters) - Sierra Leone's main opposition parties will campaign jointly against Vice-President Solomon Berewa in a presidential run-off expected next month after winning a majority in parliamentary polls, a party leader said.

No candidates reached the 55 percent required to win the Aug. 11 presidential poll outright. The opposition All People's Congress (APC) candidate Ernest Bai Koroma came closest with 44.3 percent of vote, results announced late on Thursday showed.

Here are some key facts about the country:

CAPITAL: Freetown.

POPULATION: 5.7 million. ECONOMY: Diamonds, gold, bauxite and titanium ore accounted for about two-thirds of foreign exchange income before war and instability wrecked the economy.

-- Experts said only in June that Sierra Leone has made little progress in tackling corruption and has squandered foreign aid, leaving its most vulnerable citizens as destitute as they were before the civil war ended.

-- Mains electricity and piped water are rare even in the shanty towns that make up Freetown. There are few paved roads in the rest of the country, and 70 percent of the population survive on less than $1 a day.

ETHNICITY: The Temne and Mende each account for almost one-third of the population. Lokko, Sherbro, Limba, Susso, Fulani, Kono and Krio are other important groups. RELIGION: Most of the people practise traditional African religions. Nearly one-third are Muslims, who mainly live in the north. A Catholic minority is concentrated in the capital. LANGUAGE: English is the official language but Temne, Mende and Krio (creole) are also spoken. Krio serves as the commercial language in the capital.

GEOGRAPHY: Sierra Leone covers 71,740 sq km (27,699 sq miles). It borders the Atlantic Ocean to the west, Guinea to the north and east and Liberia to the southeast. The climate is tropical.

SOME HISTORY: It won independence from Britain in 1961 and suffered years of dictatorship, coup attempts and corrupt rule.

-- President Siaka Stevens made the country a one-party state in 1978, quit in 1985 aged 80 and chose former army chief Joseph Momoh as successor.

-- Foday Sankoh's Revolutionary United Front (RUF) rebelled against Momoh in 1991, starting a decade of war that ended in early 2002 after an estimated 50,000 people were killed.

-- Having been deposed once in 1997 by a coalition of army officers led by Major-General Johnny Paul Koroma and the RUF, Ahmad Tejan Kabbah was re-elected in May 2002. The RUF, standing as a political party, won little support in the ballot.

-- A Special Court for Sierra Leone was set up jointly by the country's government and the United Nations in 2002 to try those most responsible for human rights violations during the later stages of the civil war. -- In July 2007 Sierra Leone's war crimes court sentenced three rebel militia leaders to long jail terms for "some of the most heinous, brutal and atrocious crimes ever recorded". In August it convicted two former leaders of a pro-government militia of murder and other crimes. Rebel leaders are on trial.

-- The Aug. 11 parliamentary polls were won by the opposition All People's Congress with 59 of the 112 seats. The Sierra Leone People's Party (SLPP) of outgoing President Tejan Kabbah, which dominated the last parliament, won 43 seats. The PMDC, a breakaway of the SLPP, took the remaining 10.

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