ISLAMABAD, June 15 (Reuters) - Pakistan's military has begun an all-out assault on the stronghold of al Qaeda ally and Pakistani Taliban leader Baitullah Mehsud in the South Waziristan border region near the Afghan border.
Following are some details about Mehsud.

-- In late 2007, Mehsud proclaimed himself leader of the Tehrik-e-Taliban Pakistan (TTP), or the Movement of Taliban of Pakistan, grouping around 13 factions across the country's northwest. Pakistani Taliban leaders have sworn allegiance to Afghan Taliban leader Mullah Mohammad Omar.

-- Mehsud's ascendancy came after then president and army chief Pervez Musharraf provoked a wave of militant violence by ordering troops to crush an Islamist uprising in Islamabad's Red Mosque in July 2007. Mehsud has been blamed for organising many of the suicide bomb attacks in Pakistan since then.

-- Musharraf's government and the Central Intelligence Agency both made Mehsud the number one suspect in the gun and suicide bomb attack that killed Benazir Bhutto in December 2007. Mehsud denied it, and many Pakistanis, including members of Bhutto's party, harbour other conspiracy theories about who was behind the former prime minister's assassination.

-- Mehsud was born in 1974 in Bannu, a district in North West Frontier Province that lies at the gateway to Waziristan. His ancestral village of Shaga is in South Waziristan, the poorest of seven Federally Administered Tribal Areas from the ethnic Pashtun belt straddling the border with Afghanistan.

-- In a region known for the recalcitrance of its tribes, Mehsud belongs to the Bromikhel, one of the most backward sub-clan's of the fiercely independent Mehsuds.

-- He was educated to the age of 12 in a madrasa or religious school, and is barely literate. Before becoming a full-time guerrilla leader he was a truck driver.

-- His father was a minor cleric. Clerics occupied a low rung of tribal society until the upheaval of the 1980s, when American and Saudi money and arms poured into the region to fuel the jihad, or holy war, against the Soviet occupation of Afghanistan. The turmoil of those times upset old hierarchies, and clerics became more wealthy and more influential. -- After an earlier offensive the military signed the "Sararogha" peace deal with various militant leaders in South Waziristan, including Mehsud. Some critics say the authorities effectively bought off the militants by paying "compensation" for the offensive in the tribal lands.

-- Journalists who have met Mehsud describe him as physically unimposing, round-faced beneath the mandatory beard, and he favours a traditional Sindhi cap more often than the turban common in the region. He also suffers from diabetes. He has two brothers among his followers.

(Writing by Simon Cameron-Moore, Editing by Dean Yates)