Egyptian police detained three teenage Palestinian men Wednesday on suspicion of crossing illegally into Egypt and also found explosives near the border with Gaza, security sources said.

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 Shi'ite group Hezbollah and who were plotting attacks in 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.

A prosecutor's statement has said 49 men are wanted in the alleged Hezbollah plot, which state media said was intended to target Israelis and Egyptians.

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.

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 military supplies to Gaza, not target Egypt.

The arrests have been accompanied by a barrage of criticism of Hezbollah by newspapers in Egypt, which is majority Sunni and the first Arab state to sign a peace treaty with Israel, the arch-enemy of Hezbollah and its backer Iran.