Syrian protesters and their supporters (PHOTOS)

Explosions reportedly rocked the restive Syrian city of Hama on Wednesday as government forces reportedly used heavy shelling and tanks to occupy a central square that has drawn the largest protests yet against the rule of President Bashar al-Assad, drawing international condemnation.

The raid is a continuation of a government offensive on the city that began over the weekend and has reportedly already killed around 100 people, Deutsche Welle reports.

The latest shelling started after nightly Ramadan prayers on Tuesday, while a crowd trying to rally in the central Alamein neighborhood came under rifle fire by Assad's forces, Reuters reports.

Turkey’s Deputy Prime Minister Arinc Bulent said Wednesday that the attack in Hama was an "atrocity" and a government that sanctioned such attacks against its own citizens could not be called a friend.

“I’m saying this on my behalf, what’s going on in Hama today is an atrocity … Whoever carries this out can’t be our friend. They are making a big mistake,” Arinc said, Reuters reports.

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Prime Minister Tayyip Erdogan has repeatedly urged Assad to call off his security forces and institute the reforms protesters are demanding — Assad sent a Syrian envoy to meet with Erdogan in June after Erdogan slammed acts of "savagery" that have forced thousands of Syrians to flee to Turkey.

But Arinc said the advice seemed to fall on deaf ears: "We insisted on democratic and peaceful solutions and starting reforms. We told them they would collapse otherwise … Recent events show no lessons were learned from these suggestions."

Phone lines to Hama appeared to have been cut, making it impossible to confirm events on the ground, the Scottish Daily Record quoted the head of the Syrian Observatory for Human Rights, Rami Abdul-Rahman, as saying.

"Early this morning people heard the sound of bombs," he said. "Then the phone lines were cut."

The observatory claims to take its information from sources on the ground in Syria, which has kept a tight rein on information leaving the country since unrest began five months ago.

Human rights organizations estimate that more than 1,400 people have been killed.

The UN High Commissioner for Human Rights Navi Pillay on Tuesday urged Damascus to stop the bloodshed, warning that the world is bearing witness:

"The government has been trying to keep the world blind about the alarming situation in the country by refusing access to foreign journalists, independent human rights groups and to the fact-finding mission mandated by the Human Rights Council," she reportedly said. "But they are not succeeding. The world is watching and the international community is gravely concerned."