Egyptian police detained three teenage Palestinian boy on Wednesday on suspicion of crossing into Egypt and also found what they said "explosives" near the border with Gaza, security sources said.
For the 1.5 million people in Gaza, the tunnels have become a main source of goods, including fuel, since Israel tightened its embargo after Hamas took control of the strip from the forces of Palestinian President Mahmoud Abbas in 2007.
Egypt also limits movement through its border crossing with the territory.
On Tuesday, Egypt tightened security on its border with Israel to prevent illegal crossings after authorities detained 25 men Egypt said were linked to the Lebanese Hezbollah group.
Hezbollah, which has accused Egypt of failing to help Palestinians in Gaza, has said one its members was detained and he was being helped by up to 10 others. Hezbollah said the group aimed to send supplies to Gaza, not target Egypt.
Police detained the three men, aged 16 to 18, in a dawn raid in the town of Sheikh Zweid, near the border with Gaza, the sources said.
Egypt's Sinai Peninsula is a popular tourist destination for Israelis and Egyptian media have suggested the group aimed to target resorts frequented by Israelis.
Egyptian police said they also found 900 kilograms of TNT explosives hidden in 18 sacks near the border with Gaza.
Güncelleme Tarihi: 15 Nisan 2009, 19:52