By Mohammed Ghobari
SANAA (Reuters) - Yemeni soldiers marched in a National Day parade on Tuesday, watched from behind a bullet-proof glass shield by the president, in a show of defiance one day after a bomber killed more than 90 troops in an attack on the ceremony's rehearsal.
A sombre mood hung over the event, meant to celebrate the 1990 unification of north and south Yemen, but it passed off without any repeat of Monday's bloodshed despite militant threats to carry out more attacks.
The bombing, one of the deadliest in Yemen in recent years, was a setback to the Gulf state in its battle against Islamists linked to al Qaeda and heightened U.S. concerns over a country in the front line of Washington's global war on militants.
Al Qaeda in the Arabian Peninsula (AQAP) and its affiliate Ansar al-Sharia (Partisans of Islamic Law) both claimed responsibility.
Heavy security surrounded President Abd-Rabbu Mansour Hadi and senior civilian and military officials as they watched Tuesday's parade, which was moved from the scene of the attack at Sabaeen Square to the air force academy in Sanaa.
Hadi, who took over after former President Ali Abdullah Saleh handed over power in November following months of protests against his 33-year rule, told victims' families on Monday that the fight against al Qaeda would carry on undaunted.
"The war on terrorism will continue until it is uprooted and annihilated completely, regardless of the sacrifices," Hadi said, quoted by the state news agency.
Patrols were stepped across the city and dozens of policemen were stationed at street intersections. Few people ventured out, partly due to the holiday and partly for fear of more attacks.
"We are sad for our comrades, but al Qaeda will not scare us," said Khaled al-Ansi, a soldier stationed at a street corner in central Sanaa. "We will confront it and defeat it," he added, fingers on the trigger of his gun.
The huge explosion, carried out by a man in a military uniform in the middle of the tightly-packed parade rehearsal, killed more than 90 people and wounded at least 220, according to the Defence Ministry.
One Yemeni investigator said preliminary findings suggested the bomber was a rogue soldier recruited by al Qaeda, who somehow evaded security checks.
Officials said only military cadets, rather than regular troops, took part in Tuesday's parade as a security precaution.
Turkish Ambassador Fazli Corman, who attended the ceremony, told Reuters: "Everyone was relieved at the end that it went safely, there was not a celebratory atmosphere, it was solemn."
"Not a single seat was left empty, all the foreign ambassadors were there, it was a strong message of solidarity on the part of the Yemeni government," he said.
At a NATO summit in Chicago on Monday, U.S. President Barack Obama said he was very concerned about extremist activity in Yemen and pledged more aid to counter it.
"That's important for U.S. safety. It's also important for the stability of Yemen and the region," Obama said.
Obama's counter-terrorism adviser, John Brennan, telephoned Hadi to offer U.S. help in the investigation, saying Washington "would stand by Yemen's side at this difficult time", the White House said.
Washington is increasing its support for Hadi's government and the U.S. military has targeted militants in Yemen with drones, which have frequently killed civilians and are deeply resented by Yemenis, even the many who abhor al Qaeda.
Exploiting turmoil resulting from the months of protests that helped topple Saleh, militants have seized swathes of territory in the south and threaten shipping lanes in the Gulf of Aden and the Red Sea.
The AQAP said the parade attack was in response to the "crimes" of the security forces in southern Abyan province.
Yemeni troops had closed in on the southern militant-held town of Jaar on Sunday, part of a new U.S.-backed offensive launched this month to regain control of territory and towns seized by Ansar al-Sharia.
A U.S. military trainer was seriously wounded in an ambush on Sunday claimed by Ansar al-Sharia.
(Additional reporting by Tom Finn and Sami Aboudi; Writing by Angus MacSwan)