GAZA/JERUSALEM, July 29 (Reuters) - Israel knocked out Gaza's only power plant, flattened the home of its Islamist Hamas political leader and pounded dozens of other high-profile targets in the enclave on Tuesday, with no end in sight to more than three weeks of conflict.
Health officials said at least 30 Palestinians were killed in some of heaviest bombardments from air, sea and land since the Israeli offensive began in response to Hamas rocket fire.
The Israeli assault intensified following the deaths of 10 Israeli soldiers in cross-border attacks on Monday, with Prime Minister Benjamin Netanyahu warning of a long conflict ahead.
Thick black smoke rose from blazing fuel tanks at the power station that supplies up to two-thirds of Gaza's energy needs. The local energy authority said initial damage assessments suggested the plant could be out of action for a year.
Electricity was cut to the city of Gaza and many other parts of the Hamas-dominated territory after what officials said was Israeli tank shelling of the tanks containing some 3 million cubic liters of diesel fuel.
"The power plant is finished," said its director, Mohammed al-Sharif. An Israeli military spokeswoman had no immediate comment and said she was checking the report.
Gaza City municipality said damage to the station could halt many of the area's water pumps, and it urged residents to ration water consumption.
A number of rockets were fired from Gaza toward southern and central Israel, including the Tel Aviv area. At least one was intercepted by Israel's Iron Dome anti-missile system. No casualties or damage were reported.
Outside pressure has been building on Netanyahu to rein in his forces. Both U.S. President Barack Obama and the U.N. Security Council have called for an immediate ceasefire to allow relief to reach Gaza's 1.8 million Palestinians, followed by negotiations on a more durable end to hostilities.
Efforts led by U.S. Secretary of State John Kerry last week failed to achieve a breakthrough, and the explosion of violence appeared to dash international hopes of turning a brief lull for the Muslim Eid al-Fitr festival into a longer-term ceasefire.
The West Bank-based Palestinian leadership, saying it was also speaking for Hamas and Islamic Jihad in the Gaza Strip, voiced support on Tuesday for a 24-72 hour ceasefire.
But Hamas spokesman Sami Abu Zuhri told Reuters the statement by senior Palestine Liberation Organization official Yasser Abed Rabbo did not reflect Hamas's position. "Hamas gave no approval to anything Abed Rabbo said," Abu Zuhri added.
Netanyahu said on Monday the military would not end its offensive until it destroys a network of Hamas tunnels, which Israel says serve as the group's bunkers, weapon caches and cross-border infiltration routes to attack Israelis.
The Israeli military said 70 targets were struck in Gaza during the night, including four weapons caches it said were hidden in mosques, and a rocket launcher near another mosque. Residents said 20 houses were destroyed and two mosques hit.
More than 1,100 Gazans, most of them civilians, have been killed in the conflict. On the Israeli side, 53 soldiers have been killed as well as three civilians.
HAMAS LEADER'S HOME DESTROYED
The main U.N. agency in Gaza, UNRWA, said more than 182,000 displaced Palestinians had taken shelter in its schools and buildings, following calls by Israel for civilians to evacuate whole neighborhoods ahead of military operations. Thousands more have been taken in by friends or family.
Before dawn, Israeli aircraft fired a missile at the house of Hamas Gaza leader Ismail Haniyeh, a former Palestinian prime minister, destroying the structure but causing no casualties, Gaza's Interior Ministry said.
"My house is not dearer than any of the houses of our people," Haniyeh was quoted as saying on a Hamas website. "The destruction of stones will not break our will and we will continue our resistance until we gain freedom."
Hamas, whose internal political leadership is in hiding, said its broadcast outlets Al-Aqsa TV and Al-Aqsa Radio were also targeted. The television station continued to broadcast but the radio station went silent.
The military said the stations were used to "transit orders and messages to Hamas operatives and to instruct Gaza residents to ignore IDF (Israel Defense Forces) warnings regarding upcoming military activity in specific areas."
In a televised address on Monday, Netanyahu said Israel "must be prepared for a lengthy campaign". The military warned thousands of Palestinians to flee their homes around Gaza City - usually the prelude to major army strikes.
Israel launched its offensive on July 8 saying it wanted to halt rocket attacks by Hamas and its allies. It later ordered a land invasion to find and destroy a warren of Hamas tunnels that criss-crosses the border area.
Hamas and Israel have set conditions for a ceasefire that appear irreconcilable.
Israel wants Gaza's armed groups stripped of weapons. Hamas and its allies want an Israeli-Egyptian blockade lifted.
Tension between Netanyahu's government and Washington has flared over U.S. mediation efforts, adding another chapter to the prickly relations between the Israeli leader and Obama.
In New York, U.N. Secretary-General Ban Ki-moon deplored what he said was a lack of resolve among all parties.
"It's a matter of their political will. They have to show their humanity as leaders, both Israeli and Palestinian," he told reporters.
(Additional reporting by Michelle Nichols in New York, Writing by Maayan Lubell; Editing by Jeffrey Heller and Paul Taylor)