CAIRO (Reuters) - Israeli tanks conducted a second day of probing attacks across Rafah on Wednesday, after Washington said the assault did not amount to a major ground incursion of the southern Gazan city that U.S. officials had told Israel to avoid.

Israeli tanks advanced to the heart of Rafah for the first time on Tuesday after a night of heavy bombardment, defying an appeal from the International Court of Justice to end its attack on the city, one of the last places of refuge in Gaza.

The United States, Israel's closest ally, reiterated its opposition to a major Israeli ground offensive in Rafah but said on Tuesday it did not believe such an operation was under way.

Unlike tactics used in Israel's ground offensive in the rest of the enclave, Rafah residents said Israeli tanks mounted raids into Tel Al-Sultan in western Rafah and Yibna and near Shaboura in the centre before retreating to positions near the border with Egypt.

The armed wings of Hamas and the Islamic Jihad said they confronted the invading forces with anti-tank rockets and mortar bombs, as well as blowing up previously planted explosive devices.

The Israeli military said three soldiers had been killed and three others badly wounded in combat in southern Gaza on Wednesday, without elaborating. Israel's public broadcaster Kan radio said they were hurt by an explosive device set off in a building in Rafah.

Palestinian health officials said several people were wounded on Wednesday morning by Israeli fire in the eastern area of Rafah, where they also said some stores of aid were set ablaze.

Residents said constant Israeli bombardment overnight destroyed many homes in the area, from where most people have fled after orders by Israel to evacuate.

Some residents reported seeing what they described as unmanned robotic armoured vehicles opening fire from machine guns in some parts of the city.

The pro-Hamas Shebab news agency, as well as some residents and journalists, reported internet and mobile communications blackouts in some areas of both east and west amid heavy Israeli air and ground bombardment. The Israeli military said it could not confirm the reports.

In northern Gaza, tanks shelled several Gaza City neighbourhoods, and forces thrust deeper in Jabalia, the largest of the enclave's eight biggest historic refugee camps, with residents saying large residential districts were destroyed by the army.

SEVERAL MORE HOSPITALS STOP FUNCTIONING, PALESTINIAN HEALTH MINISTRY SAYS

The health ministry said several hospitals in areas where the army is operating had stopped functioning.

Around a million Palestinians took shelter in Rafah at the southern end of the Gaza Strip following Israel's offensives in most of the rest of the enclave during more than seven months of war against the Hamas militants who run the enclave.

Around that number have now fled Rafah since after Israeli orders to evacuate, the U.N. agency for Palestinian refugees UNRWA reported on Tuesday.

The Palestine Red Crescent Society (PRCS) said it had evacuated its medical teams from its field hospital in the Al-Mawasi area, a designated civilian evacuation zone.

It cited "the increased threat level from the Israeli occupation, continued artillery and air bombardments in its vicinity, and the complete evacuation of residents from the surrounding area" in its statement, issued late on Tuesday.

In the nearby city of Khan Younis, an Israeli air strike killed three people overnight, including Salama Baraka, a former senior Hamas police officer, medics and Hamas media said on Wednesday.

The Palestinian Red Crescent said one of its staff, Issam Aqel, was killed in an Israeli air strike on his house in the Bureij refugee camp in the central Gaza Strip. It said his death rose to 30 the number of staff killed since Oct 7, at least 17 of them killed on duty.

Israel's military denied striking a tent camp in a designated civilian evacuation zone west of Rafah on Tuesday after Gaza health authorities said Israeli tank shelling had killed at least 21 people there.

Both Hamas and Gaza health officials rejected the Israeli denial, blaming Israel for what they described as a "massacre."

Nearly eight month since the war started, the two sides continued to be far from reaching a deal to cease fire and exchange hostages held captive in Gaza to a number of Palestinians held in Israeli jails.

Israel delivered its latest ceasefire and hostage release proposal to Qatar, and Qatar was to provide it to Hamas on Tuesday, a person familiar with the issue said. There was no immediate word on Wednesday from Hamas, which has said talks are pointless unless Israel ends its offensive on Rafah.

More than 36,000 Palestinians have been killed in Israel's Gaza offensive, the enclave's health ministry says.

Israel launched its air and ground war after Hamas-led militants attacked southern Israeli communities on Oct. 7, killing around 1,200 people and seizing more than 250 hostages, according to Israeli tallies.

Malnutrition is widespread in Gaza as aid deliveries have slowed to a trickle, with international aid agencies accusing Israel of blocking their distribution attempts and Israel blaming the agencies.

In a further blow to aid efforts, part of a new aid pier put in place by the U.S. military off Gaza's coast broke off, probably due to bad weather, putting it out of operation temporarily, two U.S. officials said on Tuesday.

(Reporting and writing by Nidal al-Mughrabi; editing by Philippa Fletcher)

By Nidal al-Mughrabi