Four Palestinian militants have been killed and five Israeli soldiers injured in violence in the Gaza Strip, Israeli and Palestinian sources say.
The soldiers were wounded when they were hit by a bomb as they were destroying a tunnel found last month running from Gaza to Israel.
A militant died when troops returned fire. Three more were killed in an Israeli air strike, Palestinians said.
The flare-up is one of the bloodiest between Israel and Gaza for months.
The Israeli military said the soldiers were detonating part of the tunnel on Thursday night when militants blew up an explosive device, causing casualties.