**Security forces in southern Sudan have stepped up an operation to rid the area of weapons by carrying out house-to-house searches and mounting roadblocks.**Officials swept through Juba city at dawn telling residents to stay in their homes and seizing illegal weapons.
Many in the south remain heavily armed after 22-year war with the north.
It came as US envoy Scott Gration arrived in Juba for talks aimed at paving the way for the south to hold a referendum on seceding from the north.
“*We will concentrate on finding a path forward on the two remaining unresolved sticking points *”
Scott Gration
Horrors of South Sudan massacre
The operation to disarm the south began in February, with the UN billing it as the biggest such operation in history.
But the BBC’s Peter Martell, in Juba, says the sound of gunshots in the city at night is still common.
And many Juba residents fear violent crime is on the rise in a region awash with automatic weapons, our correspondent says.
The south is reeling from a string of violent clashes which have killed 2,000 and displaced more than 250,000 this year.
Addressing rumours
Under a 2005 peace deal that ended the civil war, former rebels from the south formed a power-sharing government with President Omar al-Bashir’s party in Khartoum.
A national election is now due in 2010 and a referendum the year after.
Mr Gration arrived in Juba for two days of meetings with officials from north and south to resolve two major problems holding up the votes.
The south disputes census results saying they make up a far smaller proportion of Sudan’s overall population than they believe - which could have a huge bearing on next year’s election.
And the south wants to sort out the exact details of the referendum, amid rumours that the north intends to rig the vote.
“We will concentrate on finding a path forward on the two remaining unresolved sticking points for full CPA [Comprehensive Peace Agreement] implementation,” Mr Gration said in a statement.
“These are fundamental issues that must be resolved soon.”