GAZA CITY, Gaza Strip — Israeli troops pushed deeper into Gaza on Friday to destroy rocket launching sites and tunnels, firing volleys of tank shells and clashing with Palestinian fighters in a high-stakes ground offensive meant to weaken the enclave’s Hamas rulers.

Israel launched the operation late Thursday, following a 10-day campaign of more than 2,000 air strikes against Gaza that had failed to halt relentless Hamas rocket fire on Israeli cities.

Israel’s first major ground offensive in Gaza in just over five years came as Egyptian cease-fire efforts stalled. Earlier this week, Israel accepted Cairo’s offer to halt hostilities, but Hamas refused, demanding that Israel and Egypt first give guarantees to ease the blockade on Gaza.

Israel had been reticent about launching a ground offensive for fear of endangering its own soldiers and drawing international condemnation over mounting Palestinian civilian deaths.

It remains unclear how long the offensive will last and what Israel’s eventual goal may be — other than its stated goal of stopping the rocket attacks.

Israeli leaders have said the aim is to weaken Hamas militarily and have not addressed the possibility of driving the Islamic militants from power.

Hamas has survived Israeli offensives in the past, including a major three-week ground operation in January 2009 from which it emerged militarily weaker, but in each case it recovered. The groups controls an arsenal of thousands of rockets, some long range and powerful, and it has built a system of underground bunkers.

But Hamas is weaker now than it was during the previous two offensives — from 2008-9 and 2012 — with little international or even regional support , even among traditional Gaza supporters Turkey and the Gulf-state of Qatar.

French Foreign Minister Laurent Fabius was travelling Friday to Egypt, Jordan and Israel as part of a diplomatic push to stop the fighting in Gaza.

He said in a statement that he wants a cease-fire and lasting truce “that responds to Israel’s security needs and Palestinian economic needs.”

The operation may be its best opportunity for Israel to rid the strip of the group — which much of the world considers to be a terrorist organization.

But an operation that lasts weeks could take a heavy toll in both casualties and cost, and most Israelis have no wish to retake Gaza, which the country effectively gave up in 2005.

Egypt supports a ceasefire, but not Hamas or its conditions, which include a lifting to the siege of Gaza and completely open borders into the Sinai — where Egypt is already fighting Islamic extremists.

Israeli defense officials said soldiers faced little resistance during the first night of the ground operation, but the longer the military keeps a presence in Gaza, the greater the risk for heavy casualties on both sides.

Forces are expected to spend a day or two staking ground and are working in the north, east and south of the Gaza Strip. Then, they are expected to move to the second phase, which is to destroy tunnels, an operation that could take up to two weeks.

After thousands of troops had been on standby for several days, Israeli Prime Minister Benjamin Netanyahu said he ordered the military to prepare for a “significant expansion” of the ground offensive.