Egyptian security forces have arrested 35 people following Saturday's bomb attacks in Sharm al-Sheikh, which killed at least 88 people.
The bombs came at the height of Sharm al-Sheikh's tourist season
The arrests came after Egyptian President Hosni Mubarak vowed to hunt down those behind the bombings.
In the worst attacks in decades in Egypt, three explosions - including two apparent car bombings - devastated a hotel, a car park, and a market.
Most of the dead are Egyptians, but foreigners are among the victims too.
An Italian man on his honeymoon and a Czech citizen have been confirmed dead and at least 20 of those injured are thought to be foreign.
The BBC's Heba Saleh in Sharm al-Sheikh says Bedouins are among those detained.
She says police want to question them about unusual movements in the mountains of the Sinai.
Our correspondent says this is an area with few asphalted roads but there are many desert routes between the mountains which are used by the Bedouins.
She says police will also be seeking information about possible recent purchases of explosives in a region where they are heavily used in quarrying and for construction.
The blasts came within minutes of each other in the early hours of Saturday, when the bars and markets of the Red Sea resort were busy.
In the most devastating attack, a bomber rammed his car into the Ghazala Gardens hotel in Naama Bay, according to an eyewitness.
The front of the luxury hotel was destroyed in a huge explosion.
A few hundred metres away, a bomb went off in a car park near the Moevenpick Hotel, causing widespread damage and casualties.
In the Old Market area, about 4km (2.5 miles) away, 17 people - believed to be Egyptian - were killed by another suspected car bomb, rescue officials said.
The bombings happened at the height of the summer tourist season, and coincided with an extended holiday weekend to mark the anniversary of the 1952 Egyptian revolution.
They came less than a year after attacks at a resort further north in the Sinai peninsula left 34 people dead.
Egyptian Interior Minister Habib al-Adli said he cannot exclude a connection between the two incidents.
Egypt blamed the 2004 attack on a Palestinian man leading an unaffiliated group.
In a statement posted on an Islamic website, a group calling itself the Abdullah Azzam Brigades, al-Qaeda, said it carried out the bombings.
However, the statement did not appear on well-known al-Qaeda websites and it was impossible to authenticate the claim.
President Mubarak has vowed to hunt down the perpertrators.
"This will only make us more determined to pursue terrorism and eradicate it," said President Mubarak after visiting the bomb scenes.
"We will not give in to its blackmail, or seek a truce."
US President George W Bush has meanwhile condemned the "barbaric terrorist attacks", which he said were an "assault on the civilised world".
The previous worst attack in Egypt was in 1997, when Islamic militants killed 58 foreign tourists and four Egyptians near the southern city of Luxor.
The tourism industry - Egypt's most lucrative - has slowly recovered since that attack, but there are widespread fears that these latest bombings will deal it a fresh blow.