Four Palestinian militants have died in a clash with Israeli soldiers along the Israel-Gaza border, medics and officials in the Hamas-run Strip say.
Up to 10 Palestinian gunmen tried to cross the heavily fortified border into Israel, Palestinian officials said.
The Israeli military says troops opened fire after being shot at by the gunmen.
It is one of the most serious outbreaks of violence between Israel and militants from Gaza since the end of a three-week conflict in January.
The clash is reported to have taken place close to the Karni and Nahal Oz crossings in the north-east of the Gaza Strip.
Reuters news agency quoted a Hamas radio station as saying that 10 Palestinian militants - some on horseback - attempted to cross the border under cover of early-morning fog.
No Israeli casualties have been reported.
Gaza has been relatively quiet since Israel's three-week offensive against Hamas ended on 18 January.
But sporadic violence along the border continues.
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