A girl injured in the earthquake in Pakistan's Awaran area, receives medical treatment after she was brought to a local hospital in Awaran, Balochistan province, Pakistan, 25 September 2013. (MUSA FARMAN/EPA)

One day after a major earthquake struck a remote region of southwestern Pakistan, authorities reported Wednesday that the death toll had risen to at least 325 and confirmed that the temblor’s force had created a new, albeit probably temporary, island in the Arabian Sea.

The magnitude-7.7 quake was centered in the impoverished, sparsely populated province of Baluchistan and appeared to have leveled entire villages. On Wednesday, Pakistan’s army rushed 1,000 soldiers, helicopters, food and medicine to the area as officials braced for a grim and long-lasting rescue operation.

The death toll was expected to rise as workers sifted through thousands of collapsed homes, many made of dried mud.

“The devastation in these areas is massive,” Jaan Muhammad Baledi, a spokesman for the Baluchistan government, told Pakistan’s Geo TV. “The quake affected areas that are remote, and there are few roads which lead to them. Conditions are bad, thus making it difficult for relief activities.”

Prime Minister Nawaz Sharif, who is in New York for the U.N. General Assembly, said federal officials were trying to quickly assess the situation and dispatch needed resources.With hundreds of injuries reported, army helicopters were attempting to evacuate some patients to Karachi for treatment.

Pakistan’s Red Crescent Society has also rushed to the scene, amid reports that tens of thousands of families may have been left homeless.

Baluchistan has been unstable and largely isolated for years because of an ongoing military conflict between security officials and Baluch separatists. The mineral-rich province has also become a haven for militants and terrorist groups, including the Pakistani Taliban and Lashkar-e-Jhangvi, a hard-line Sunni militant organization affiliated with al-Qaeda.

According to the Associated Press, one group of Pakistani security forces was fired upon Tuesday night while escorting a convoy of doctors to areas hit hard by the quake.

Within minutes of the temblor, which was felt as far away as New Delhi, residents of Baluchistan’s far southwestern Gwadar district reported a new island less than a mile offshore in the Arabian Sea.

On Wednesday, Pakistan’s National Institute of Oceanography confirmed the existence of the island, estimated to be about 200 feet long and 30 feet high. Onlookers were photographed climbing on the mass Wednesday, but officials warned that it might be emitting dangerous gases.

Asif Inam, the institute’s principal scientific officer, said the island formed after the quake forced methane gas from the ocean floor. He said a similar island had appeared after a quake in 1945, then again in 1999 and 2010, even without seismic activity.

“The island popped out of nowhere because there is just a huge amount of gas pressure in that area,” Inam said. “Whenever there is an opportunity, it escapes out and creates a gap.”

The earlier islands eventually settled below water, and Inam said this one won’t last long, either. “It will definitely collapse back,” he said. “It will be within a couple months.”

Over the past decade, Pakistan has endured several catastrophes, including a magnitude-7.6 earthquake in the far north in 2005 that killed at least 40,000 people. Five years later, 1,700 people were killed and more than 1 million homes destroyed during severe monsoon flooding in the south.

Haq Nawaz Khan and Shaiq Hussain contributed to this report.