The Israeli army continued to launch strikes in southern Gaza on Thursday, responding to mortar attacks on its troops along the border.

Health officials in Gaza said a 54-year-old woman was killed near Rafah by an Israeli tank shelling. In a separate incident, four members of the same family were wounded - three children and a 65-year-old man - in an airstrike on a workshop in Gaza's Al-Zeitoun district.

The confrontation began on Wednesday when the Israeli military discovered a tunnel dug by Palestinian armed groups underneath the southern Gaza border. Since then, Hamas and other Palestinian militant groups have fired mortar rounds at Israeli ground troops on at least 10 occasions. The Israeli army responded with ground and air raids.

The Islamic Jihad group claimed responsibility for firing at least five mortar shells on Israeli forces.

Memories of 2014 conflict

Israeli and Hamas spokesmen on Thursday sought to play down fears of fresh warfare akin to their 50-day conflict in 2014, which ended with a fragile ceasefire that has largely held for two years.

Hamas official Mousa Abu Marzouk said Egypt and Qatar had intervened in bids to restore calm. Israeli army spokesman Peter Lerner said Israel had "no interest in escalation whatsoever."

Overnight, Israeli aircraft targeted "four Hamas infrastructure sites" in the northern Gaza Strip after troops came under mortar fire, Israel's military said.

New tunnel found

Lerner said Hamas had fired at least six times at Israeli troops after they discovered a new Hamas tunnel stretching into Israeli territory at a depth of 30 meters (about 100 feet). No casualties were reported.

"The IDF [Israeli Defense Force] exposed a second tunnel in the southern Gaza Strip," he said, confirming that the find was made by Israeli forces inside Gaza.

Israel destroyed another tunnel last month, heightening Israeli concerns that Hamas might be rebuilding its underground network to conduct attacks against Israel.

Lerner speculated Hamas militants had opened fired because they realized that Israel had been closing in the latest tunnel.

"It's something we are not prepared to tolerate," he said.

Last month, Israeli Prime Minister Benjamin Netanyahu hailed a "global breakthrough in the ability to locate tunnels," without disclosing further details.

UN envoy urges restraint

On Wednesday, the UN special coordinator for the Middle East peace process, Nickolay Mladenov, said he was "concerned" about the latest flare-up.

"It is critical that peace be maintained to ensure the safety and security of Israelis and Palestinians alike," said Mladenov.

Late Wednesday, Palestinian leaders said they would no longer tolerate Israeli raids into Palestinian cities by "immediately" implementing a March 2015 decision to suspend security cooperation with Israel.

Israel insists that such raids are necessary to foil plans by radicals.

shs,ipj/cmk (dpa, AP, AFP)