Israeli warplanes pounded Hamas-ruled Gaza early Tuesday in response to Palestinian fire balloon attacks across the border, the Israeli army said.
The strikes came as visiting Egyptian security officials strove to defuse the latest uptick in violence, a Hamas source said.
"Fighter jets and (other) aircraft struck underground infrastructures belonging to the Hamas terror organisation in the Gaza Strip," an Israeli military statement said.
It linked the air strikes to "explosive and arson balloons launched from the Gaza Strip into Israel".
The Hamas source told AFP the Islamists had held talks with the Egyptian delegation in Gaza on Monday before it left the territory for meetings with the Israelis and the West Bank-based Palestinian Authority.
It was expected to return to Gaza after those talks were concluded, the source added.
Despite a truce last year backed by Egypt, the UN and Qatar, Hamas and Israel clash sporadically, with Palestinian incendiary balloons or rocket or mortar fire drawing retaliatory Israeli strikes.
"The occupation continued its aggression and carried out air strikes on Gaza after midnight," the Hamas source said, adding that the strikes were seen as a "negative response" to the truce feelers.
There were no casualties in the strikes, he added.
Gaza security sources and witnesses said the strikes hit Hamas lookout posts at Rafah in the south of the territory and Beit Lahia in the north.
Tensions have been rising for more than a week, with Hamas firing rockets and launching bundles of balloons across the border fitted with incendiary or explosive devices.
In response, Israel has closed its Kerem Shalom goods crossing with the Gaza Strip, imposed a ban on fishing off the Gaza coast and, in the past few days, staged nightly air raids.