Egyptian police Wednesday said the three were detained in the North Sinai town of Sheikh Zweid, which is about 15 kilometers from the Egyptian border with Gaza and Israel. Police report finding 900 kilograms of TNT packed in bags.
The arrests and the discovery of the explosives came a day after Egypt tightened security on its border with Israel following the arrest of 25 suspected members of a Lebanese Hezbollah cell. Egyptian authorities accused the cell of plotting attacks in Egypt.
On Sunday, Egyptian state media called Hezbollah chief Hassan Nasrallah a criminal after he admitted that his group is operating inside Egypt.
Nasrallah also confirmed that Egyptian police recently arrested a Hezbollah member who was helping to smuggle weapons to the Palestinian militant group Hamas in the Gaza Strip.
Egyptian state-run newspaper al-Gomhouria devoted its entire front page Sunday to an editorial ridiculing Nasrallah as a "monkey sheikh." The newspaper's editor accused Nasrallah of killing his own people, and he said Egypt will not allow the Hezbollah chief to threaten its security.
Hezbollah has been a strong critic of Egypt's government for refusing to permanently open the Egypt-Gaza border since Hamas took control of Gaza in 2007. It also accuses Cairo of not doing enough to stop a recent Israeli offensive in Gaza.
Egypt views Hezbollah and Hamas as proxies of Shi'ite-dominated Iran, and is worried about what it sees as growing Iranian influence in the region.