Six Palestinians were trapped and another was missing Thursday after a Gaza smuggling tunnel collapsed, a local Hamas official said.
He described the underground passage from the southern Gaza town of Rafah into neighbouring Egypt as a "trade tunnel."
The cave-in, the sixth since January, was caused by Egyptian flooding of the border zone in its campaign to stop smuggling, the official told AFP.
Authorities have spoken to one of the trapped men by mobile telephone and rescue efforts are under way, he added.
Since January 26, 12 Gazans have been killed in five separate tunnel collapses – most of them Hamas terrorists – with both Israel and Egypt operating against the diggers.
An Israeli blockade is still in place to prevent advanced weapons and other potentially lethal equipment reaching terrorists in Gaza, and Egypt's sole border with Gaza has also remained largely closed since 2013.
The passages to Egypt are used for transit of commercial goods, cash, people and weapons. Much of the goods flowing into and out of Gaza are coordinated with the Egyptian branch of the so-called Islamic State (ISIS) terrorist group, known as "Sinai Province."
In late 2014, as part of an attempt to restore peace in its restive northern Sinai region, Egypt began setting up a buffer zone on its border with Gaza and destroyed hundreds of tunnels.
At the other end Gaza, near the border with Israel, Gaza's Islamist Hamas rulers have built tunnels to avoid or launch attacks, store weapons and at times to stage raids into Israel.
AFP contributed to this report.