Major-General Yoav Mordechai, who oversees Israel's civilian policy towards Gaza, named members of Hamas's military wing he said were involved in training fighters of Islamic State, also known as ISIS, and smuggling wounded from Sinai into Gaza for treatment.
"We know that Hamas and I have verified information, that Hamas in Gaza is assisting ISIS Sinai Province both in organisation and armaments," Mordechai said.
He named two Hamas members, saying Abdallah Qishta was involved in training Islamic State members in Sinai and Wael Faraj, a battalion commander, had "smuggled terrorists from Sinai into Gaza Strip hospitals for medical treatment".
It is not clear how the militants would have been moved into Gaza given that Egyptian forces control the border, but there are believed to still be tunnels between the two sides that Egypt has not yet found and destroyed.
Hamas, which has rejected similar accusations made by Egypt in the past, said Mordechai's charges were an attempt to damage its relations with Cairo. It denied any involvement in Egypt.
Hamas, an Islamist group that seized power in Gaza in 2007, has faced its own threats from Salafist and ISIS-linked militants in recent weeks. On Tuesday, Islamic State militants released a video threatening to turn Gaza into another of their 'fiefdoms', as in parts of Iraq and Syria.
Israel and Egypt have coordinated in putting pressure on Hamas in Gaza, with Israel enforcing a blockade of the territory and limiting the flow of goods and people, while Egypt has largely kept its border crossing at Rafah closed.

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