Israel accused Hamas on Tuesday of supporting last week's assaults by Islamic State affiliates on Egyptian forces in the Sinai in hope of freeing up arms smuggling to the Gaza Strip.
The remarks followed Israeli allegations that Hamas members provided training and medical treatment for the Sinai insurgents – charges dismissed by the Palestinian Islamist group as a bid to further fray its troubled ties with Cairo.
Egypt said more than 100 insurgents and 17 of its soldiers were killed in Wednesday's simultaneous assaults, carried out against military checkpoints around the North Sinai towns of Sheikh Zuweid and Rafah. Islamic State's Egypt affiliate, Sinai Province, took credit for the attacks.
Rafah straddles the border between Egypt and Gaza and had long seen smuggling to the Hamas-controlled enclave. But Cairo has been cracking down on such activity and deems Hamas a threat to Egyptian interests.
An Israeli intelligence colonel responsible for monitoring the borders with Egypt and Gaza said on Tuesday that Hamas, short of weaponry after its war against Israel last year, supported the Sinai assaults with the "objective of opening up a conduit" for renewed smuggling.
"Why was it is so very important for them (Hamas) to develop the connection with Sinai Province? Because they need the raw materials that would enable the military build-up in Gaza," the colonel said in remarks aired by Israel Radio.
"To carry out high-quality smuggling required a special operation," added the colonel, whose name was not published.
Hamas said Israel was conducting "a systematic incitement campaign".
"The Egyptian side understands that Hamas had no connection to what happened in Sinai and also realises the efforts Hamas is making to to keep Gaza away from what happens there," said Sami Abu Zuhri, a spokesman for the Palestinian movement.
Egyptian officials were not immediately available to respond to the Israeli colonel's allegations.
On Friday, Egyptian military sources said there was evidence that individuals from Hamas had participated in the Sinai battles but not of any wider organisational links.
Though they share hostility to Israel, Hamas and Islamic State have been at odds within Gaza. The insurgents threatened last week to extend their self-declared caliphate in Syria and Iraq to Gaza by toppling Hamas, which they described as insufficiently stringent about religious rule.
That strife ends at the Sinai border, Israel argues.
"Hamas is fighting ISIS (Islamic State) in the Strip, but on the other side there is cooperation between Hamas elements from Gaza and ISIS in Sinai," Israeli Defence Minister Moshe Yaalon said in a statement on Tuesday.