"It is a catastrophe," he says a day after a foiled bombing and shooting attack at the ancient site, afraid that tourists will never return and that he will be deprived of his bread and butter.
"Of course this incident will affect our lives," says Nasser, 47, a father of five who depends on sales of souvenirs to raise his family.
All around him, his colleagues shake their heads in agreement because, they say, tourism is their only source of income.
The police say they prevented a "massacre" in Karnak Wednesday when assailants widely believed to be jihadists tried to carry out an attack at the ancient site.
One of them killed himself by setting off the explosive vest he was wearing, while police killed an accomplice and seriously wounded the other.
"I am afraid for tomorrow. I have five children. I want to be able to (earn money) to offer them an education," said Nasser.
Ahmad Gamal, another souvenir merchant, agrees.
"These past four years have been bad enough. Imagine the consequences of a terrorist attack," he said.
Egypt has been rocked by upheaval and deadly violence since the 2011 uprising that toppled long-time president Hosni Mubarak and the overthrow of his Islamist successor in 2013 by the army.
"Tourism will totally collapse; tourists will not return," said Gamal.
On Thursday there were more police than tourists in the streets of Luxor, particularly outside the many Pharaonic sites.
Only seven coaches and three minibuses were seen parked mid-morning around the Karnak temple, a complex of temples dedicated to the ancient gods that was built over 2,000 years.
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- Tourist cancellations -
Only about 200 tourists strolled through the vast open-air museum that is Karnak, as Gamal, Nasser and others vendors tried desperately to attract their attention and make a sale.
Although June is considered low season for tourism because of the sweltering heat that envelopes Upper Egypt, some tourists still come on organised trips from sea resorts.
Tourist guide Hamada Nagui had expected a Russian group to come for the day from Hurghada but they cancelled.
"This is a great loss for us," said Nagui.
And he immediately lashed out at the security forces, blaming them for failing to provide the visitors with the adequate protection, although no tourists were hurt Wednesday.
"They always search Egyptians meticulously, but hardly look at foreigners. The terrorists were disguised as tourists and what did the police do? Nothing."
The prosecutor handling the investigation, Wael Abu Deif, told AFP the assailants "pretended to be tourists" and had been able to enter the parking lot of the site "without any proper security".
"We are angry that the terrorists were able to get to the parking area so easily," said another guide, Hagag Abdel Hamid.
Wednesday's foiled attack is a blow to efforts by Egypt to woo back tourists and revive an industry that has been badly hit by four years of unrest and militants attacks on security forces.
But experts believe jihadists have now decided to target the Achilles' heel of tourism and investments in order to weaken the government, which has pledged to fix the battered economy.
About 10 million tourists visited in 2014, down sharply from a 2010 figure of almost 15 million people drawn to the country's archaeological sites and Red Sea resorts.
"A large group was expected to arrive on Thursday night from Britain but they cancelled," said the manager of a four-star hotel on the banks of the Nile River.
"At least 160 tourists have decided not to come" to Luxor.