|Yemeni authorities have deployed extra security at the stadiums and around the visiting teams' hotels [AFP]
Yemen has put in place unprecedented security measures ahead of the 20th Gulf Cup football tournament that kicks off on Monday.
Some 30,000 extra troops have been deployed due to fears the cup of nations could be targeted by al-Qaeda or other armed groups.
The authorities will provide extra security at the stadiums and around the visiting teams' hotels, general Saleh Zawara, the tournament's security chief, said.
He said there would be six security cordons around each of the venues.
On Tuesday, activists of the Southern Movement, a coalition of autonomist and pro-independence groups, vowed in a statement to try to disrupt the tournament.
Yemeni prosecutors implicated Shalal Ali al-Shaea, one of the movement's leaders, in twin bomb blasts in Aden in October.
The south was independent from 1967 when the British withdrew until it united with the north in 1990. It seceded in 1994, sparking a brief civil war that ended with it overrun by northern troops.
Many residents complain of discrimination by the Sanaa government in the distribution of resources and the region has seen a spate of violent protests in recent months.
Al-Qaeda safe haven
It has also witnessed growing violence by al-Qaeda, which has found safe haven in the south and east of Yemen, Osama bin Laden's ancestral homeland.
Al-Qaeda in the Arabian Peninsula (AQAP), the armed group's Yemen-based wing, has vowed to "bleed" US resources with inexpensive, small-scale attacks that cost billions for the West to guard against.
AQAP said it had spent just $4,200 on two parcel bombs mailed from Yemen to the US last month. The bombs were intercepted in Britain and Dubai, sparking a worldwide security alert.
Admiral Mike Mullen, the top US military officer, called AQAP a serious threat to the US on Sunday, adding that it has become substantially more dangerous over the past two years.
Yemeni officials have been at pains to reassure the countries taking part in the Gulf Cup that the tournament can go ahead safely.
Ali Abdullah Saleh, the president, visited the port city Aden on Friday, where he inspected the facilities for the tournament and held meetings with organisers and security officials.
Saleh paid tribute to "the efforts of the security services and military to ensure that the tournament takes place peacefully and securely".