The soldier, named as Hadar Goldin, 23, disappeared when Israeli forces trying to destroy a suspected militant tunnel were attacked, Israel's military said.
Update, August 1, 8 p.m.: Hamas says it is not holding any Israeli soldiers.
The cease-fire lasted two hours. From Haaretz:
Mortar shells fired from within the Gaza Strip landed near a border-region town some two hours after the truce deal brokered by the United States and the EU kicked in, and shortly thearafter Palestinian medical sources reported that at least 25 Gaza residents were killed and dozens of others wounded by IDF artillery fire directed at the southern Strip.
Israeli soldier Gilad Shalit was captured by Hamas in 2006 and held for five years; Israel ultimately agreed to exchange 1,027 prisoners for his freedom.