Yemen stepped up security around government buildings and foreign embassies and offices on Tuesday, a day after a suspected Al-Qaeda suicide bomber killed seven Spanish tourists and two Yemenis at a tourist site.
President Ali Abdullah Saleh, whose country joined the US-led war against terrorism after the September 11 attacks, said Yemen had received warnings last week of an impending attack but did not know where or when the militants would strike.
He offered a $75,500 reward for information leading to the capture of militants linked to the attack at the Queen of Sheba Temple in the volatile province of Marib.
"The security apparatus had information about four days ago but did not know exactly when or where this operation would be carried out," Saleh told a news conference.
"Security measures were taken around sensitive sites such as oil installations but we did not think of this temple."
Security sources told Reuters that Al -Qaeda issued a statement last week demanding the release of some of its members jailed in Yemen, which has been battling Islamist militants for years, and threatening to take unspecified action.
The fortified US embassy in Sanaa cancelled all travel outside the capital and warned its citizens against travel to Marib, urging them to be vigilant throughout the country.
Yemen, viewed in the West as a haven for Islamist militants including Al- Qaeda, has seen several spectacular bombings.
Witnesses in Marib said body parts were strewn around the charred vehicles used by the Spaniards. One resident said the blast was strong and heard for miles around.
DNA tests were being carried out on the remains of the suicide bomber to try to ascertain his identity, Saleh said, adding that evidence so far indicated he was a non-Yemeni Arab.
Yemeni Interior Minister Rshad al-Alimi told reporters in a joint news conference with Spain's Industry, Tourism and Trade Minister Joan Clos that Sanaa would welcome the participation of Spanish investigators in the probe.
Clos arrived in Yemen late on Tuesday with members of victims' families to take home loved ones for further medical attention and some came to accompany the bodies of those killed.
Blow to tourism
Spain was sending two planes to Yemen to pick up the remains of the three men and four women killed in the attack and to take five wounded survivors home, Yemeni and Spanish officials said.
One of the wounded, a woman in her 50s with severe head injuries, will undergo a second surgery in Yemen before she can be transported, Health Minister Abdul-Karim Rase said.
"She has a deep brain injury and she is in a coma. The Spanish officials agreed that she should stay and a Spanish doctor will take part in the surgery," Rase told Reuters.
Ordinary Yemenis were saddened by the attack and one described it as "really shameful".
"This incident is a blow to the national economy and will affect tourism but should not affect investment," Saleh said.
"I told the Interior Ministry to award 15 million riyals to whoever offers information leading to the capture of these terrorist elements or their siege or killing
One of the poorest countries outside Africa, Yemen has been trying to encourage tourists put off by kidnappings and bomb attacks and boost foreign investment as its oil dwindles.
Yemen foiled two suicide attacks on oil and gas installations in 2006, days after Al -Qaeda urged Muslims to target Western interests. Al Qaeda's wing in Yemen claimed responsibility for the foiled attacks and vowed more strikes.