Palestinian President Mahmoud Abbas will chair a congress of his Fatah movement today – the first such gathering of the group in 20 years.Secular Fatah has dominated Palestinian politics for decades. The three-day convention is seen as a chance to re-energise the faction and pursue reform. Delegates are meeting in the West Bank city of Bethlehem. More than 2,000 are expected, including veterans living in exile who have been given permits by Israel to take part. Participants from Syria, Lebanon and Jordan are among those arriving with Israel’s consent, which in some cases has raised eyebrows. Khaled Abu Usba, for example, was part of a Fatah cell that infiltrated into Israel in 1978. Having served time in an Israeli jail over a bus hijacking that left 36 people dead, he is now attending the Fatah Congress. But the rival movement Hamas, which seized control of Gaza in fighting in 2007, has forbidden Fatah members living there from taking part. The Islamist group wants Hamas prisoners freed from West Bank jails first and has threatened legal action against any Fatah delegate defying the ban.