A smuggling tunnel running under the Gaza-Egypt border collapsed on Monday, killing one person and injuring two, Hamas officials said.
Hamas said that three other people were missing.
Israel and Egypt have blockaded Gaza since the Hamas seized power there in June 2007.
Israel has often bombed the tunnels to try to stop weapons smuggling.
No reason was given for Monday's collapse. More than 100 Palestinians have died in tunnel collapses this year. Twelve were killed last week.