GAZA CITY, Gaza Strip »  Israeli strikes hit two media centers in the Gaza Strip on Sunday, as Israel warned it was widening its range of targets to go after military commanders of the territory’s Hamas rulers. Palestinian militants meanwhile fired at least one more long-range rocket at Tel Aviv, the fourth day in a row which the Israeli heartland has come under fire.

The Israeli strikes, apparently missiles, hit two high-rise buildings. They damaged the top floor offices of the Hamas TV station, Al Aqsa, and a Lebanese-based broadcaster, Al Quds TV, seen as sympathetic to the Islamists.

A Gaza press association said six Palestinian journalists were wounded. Foreign broadcasters, including German and Italian TV outlets, also had offices in the high-rises.

The Israeli military said it was aiming at a communications antenna on the roof of one of the buildings. It had no immediate comment on the other strike.

The military also said another long-range rocket was launched at Tel Aviv, but that it was intercepted by the "Iron Dome" missile defense system. Police spokesman Micky Rosenfeld said that two rockets were fired. It was impossible to immediately reconcile the two reports.

On Sunday, five Palestinian civilians were killed in airstrikes, including four children ranging in age from one to seven, according to Ashraf al-Kidra, a Gaza health official. Two of the children, a 3-year-old girl and a 5-year-old boy, were from the same family and were killed by an airstrike on their home in the Jebaliya refugee camp.

The deaths bring to 51 the number of Palestinians killed since the operation began on Wednesday. One third of the dead were civilians, and more than 400 civilians have been wounded, al-Kidra said. On the Israeli side, three civilians have been killed and more than 50 wounded by rocket fire.

Israel’s military spokesman warned that Israel would go after Hamas commanders Sunday, in addition to rocket squads, in "more targeted, more surgical and more deadly" attacks.

Brig. Gen. Yoav Mordechai made the threat as Israel found itself at the crossroads of whether to launch a ground invasion or pursue Egyptian-led truce efforts. Israel has said it is not prepared to enter into a truce without guarantees the rocket fire won’t resume.

Early Sunday, the military carried out dozens of attacks on rocket-launching sites, a major training base and the attacks on the two media centers. Israeli gunboats also fired on militant sites on the Gaza shore line, the military said without elaborating.

Gaza militants have widened their rocket range, compared to previous conflicts, firing rockets toward Tel Aviv and Jerusalem and putting 3.5 million Israelis, or nearly half the country’s population, within reach.

Mordechai, the Israeli military spokesman, told Army Radio that despite truce efforts, the military has been ordered to intensify its attacks, following a late-night meeting led by Prime Minister Benjamin Netanyahu and Defense Minister Ehud Barak.

"I imagine in the next few hours, we will see ongoing targeted attacks on gunmen and Hamas commanders," Mordechai said. "More targeted, more surgical and more deadly."

Israel launched its military campaign on Wednesday, after months of renewed rocket fire from Gaza, by assassinating Hamas’ military chief in an airstrike. Since then, it has relentlessly targeted suspected rocket-launching and storage sites.

Israeli Defense Ministry director Udi Shani told Army Radio that Israel’s operation against Gaza militants was not meant to topple the Islamic militant Hamas, but to cripple its capabilities to attack Israel.

"If we don’t achieve our goals from the air, we will have to enter by ground," Shani said. "I hope in the coming days it will be decided."

The air attacks initially focused on Hamas military targets, but gradually have expanded to include symbols of Hamas power.

Six journalists were wounded in the attacks on the media targets, including one who lost a leg, the Gaza journalists’ association said.

Bassem Madhoun, an employee of Dubai TV, said two missiles scored a direct hit on Al Aqsa TV’s 15th floor offices in one of the buildings.

Building windows were blown out and glass shards and debris were scattered on the street below. Some of the journalists who had been inside the building at the time took cover in the entrance hallway.

Mohammed Shrafi, a Palestinian cameraman, said he was in the street filming when he was hit by shrapnel coming down from the building.

Asked why Israel was targeting media centers, he replied, "they want to keep us from telling the truth."

The Israeli military also appeared to take over the frequencies of the radio stations of Hamas and the Islamic Jihad militant group to broadcast a recorded, Arabic-language warning to the people of Gaza to stay away from Hamas installations and personnel.

"To the people of Gaza, Hamas is playing with fire and gambling with your fate," said the message, which was broadcast every five minutes. "The Israel Defense Force is moving toward the second phase of its operation. For your safety, you should stay away from Hamas infrastructure and personnel."

The message did not say what the "second phase" was, but thousands of Israeli troops are massed near the Gaza border, awaiting an order to invade should Israeli leaders decide on that course. Israeli Vice Premier Moshe Yaalon told Army Radio that Israel has to be prepared to widen the operation if militants don’t back down.

The military spokesman’s office said it could not confirm it was broadcasting this message, but said it has issued similar warnings over the radio several days ago.

In Iran, Israel’s arch-foe, parliament speaker Ali Larijani urged Islamic countries to send weapons for Palestinians.

"Today, serious military help is expected. Why can the United States and the West hand over weapons to the Zionist regime, or Israel, but weapons should not be given to Palestine?" state radio broadcast Larijani telling parliament.