A police source said 25 Bedouins had been arrested after an exchange of fire with police in the hills inland from the hamlet of el-Ruwaisat, north of Sharm el-Sheikh.
Security sources earlier said the Bedouins were believed to be protecting two Pakistanis wanted for questioning but authorities later played down that version.
Authorities said police had been able to track the course of two vehicles used in the attacks and that the suspected bombers came over the mountains from the northern hamlet of Ras Sidr, on the west coast of the Sinai peninsula, posing as quarry workers.
At least 64 people, mostly Egyptians, died in the attacks, Minister of Tourism Ahmed el-Maghrabi said. That figure, however, does not take into account additional body parts.
Officials at Sharm el-Sheikh International Hospital on Saturday put the number of dead at 88.
At roadblocks in and near Sharm el-Sheikh, authorities distributed photographs of some 50 foreigners, including five Pakistanis, who police said may be linked to the attacks. A security source later said the Pakistanis were wanted for questioning and that they were not the prime suspects.
Some of the 50 people wanted for questioning were "known international terrorists", security sources said.
Police named Pakistanis Mohammad Anwar, 30, Rashid Ali, 26, Mohammad Akhtar, 30, Tasadduq Hussein, 18 and Mohammad Arif, 36, but, sources said, it was unclear if they had been staying in the town.
Arab satellite channels said up to nine Pakistanis had been staying in hotels in Sharm el-Sheikh but disappeared after the bombings early on Saturday morning, leaving their passports at reception. Al Jazeera said the suspects might have entered the country using forged Jordanian passports.
A Pakistani embassy official in Cairo told Reuters his country was urgently requesting information from the Egyptian authorities. In Islamabad, Pakistan's Foreign Ministry spokesman said Pakistanis were unlikely to have been involved.
In the first political casualty after the bombings, Police Major-General Hamdi Ghali, who is the police chief in the Egyptian province of South Sinai, lost his job and is under investigation, official sources said on Monday.