Hundreds of shoppers Saturday thronged through the re-opened Westgate Shopping Mall in Kenya's capital, Nairobi nearly two years after an extremist attack there left at least 67 people dead.

Nairobi Governor Evans Kidero cut a ribbon during the ceremony which came after two years of repairs from the damage caused by security forces battling four gunmen from Somalia's Al Qaeda-linked al-Shabab group in September 2013.

The attack on the upscale shopping center shocked the nation and led to a four-day siege by security forces, which destroyed part of the roof when the army fired rocket propelled grenades to dislodge the attackers.

"We could have been hurt but our spirits have not been broken, it is a demonstration of the determination and the positivity and the resilience and the indomitable spirit of the Kenyan people," said Kidero. "I know there will be apprehensions but, as a country, we are safer."

Brighton Salamba, 25, the manager at Tapas Ceviche Bar, said he was happy to finally be back at work and described how he underwent counselling sessions paid for by his employer to get over the trauma from the experience.

He managed to escape the attackers by locking the door of the restaurant and crawling up a ventilator shaft with 25 other people. The group moved through the ducts until they reached another restaurant and fled through an exit, Salamba recalled.

"I thanked God. We could hear the screams and gunshots," he said. "We lost two colleagues in the attack."

Shoppers will get a 10 percent discount for every $30 spent at the 80,000 square foot complex which is expected to employ more than 250 staff.

American fast food chain Pizza Hut will also open for the first time in Kenya at the mall.

Al-Shabab justified the attack as revenge on Kenya for sending its troops to Somalia to fight the militants.