By Alberto Dabo
BISSAU, July 17 (Reuters) - Guinea Bissau questioned gunmen on Sunday over an attack on the presidential palace and interior ministry that has spread fear through the coup-prone West African country a week ahead of a presidential runoff vote.
Saturday's attack, which killed at least two policemen, prompted some residents to pack up and leave the impoverished capital Bissau, plagued by years of violence and military coups.
The attack added to tensions ahead of the July 24 runoff vote -- meant to restore constitutional rule -- between former military ruler Joao Bernardo Vieira, commonly known as "Nino", and Malam Bacai Sanha of the main political party, the PAIGC.
Security forces repelled the attack and Interior Minister Al Adji Mumini Embalo told reporters later on Saturday that 10 attackers and 10 other suspects were arrested but it was unclear who was behind the dawn raid or what its motive had been.
Police said on Sunday they were still interrogating the group at the interior ministry building.
The army went on maximum alert on Saturday, when it appealed for calm, saying the dawn raid was an isolated incident with no link to members of the military or paramilitary forces.
The gunfire prompted some residents to abandon their homes in Bissau and head for their homes upcountry.
"THE COUNTRY IS SICK"
"The country is sick and we are scared, that is why we are leaving," Elsa Correia, a woman in her 20s, said on Sunday as she waited at a bus station with her younger brother and sister for a minibus heading to Mansoa, 50 km (30 miles) away.
Fatou Drame, whose husband works in former colonial power Portugal, hoped she and her five children would be safer in Gabu, 200 km 125 miles) from Bissau.
"I've locked up the house, but I don't know whether it will be looted while we are away," she said, standing at the same station with a bag of possessions on her head.
"I'm worried about my children's schooling -- I don't know now whether they will get registered with a school in Bissau for the next academic year."
Nevertheless, the exodus was far smaller than some of those seen after previous bouts of violence in Bissau. Clashes between security forces and supporters of former President Kumba Yala paralysed Bissau after results from the first round of polls held on June 19 showed he had come third. Four people were killed in the violence.
Yala, who declared himself president in May and was accused of attempting a coup shortly afterwards, eventually accepted the results. He denies any involvement in the coup attempt.
Yala won a 1999 election designed to restore democracy but his tenure was marked by a sequence of uprisings and political crises and he was toppled in 2003 a military coup.