The Islamic State (ISIS) launched a chemical weapons attack against Kurdish Peshmerga forces in Northern Iraq on Thursday, sickening over 100 people, CBN News reported.

It was not the first time that ISIS has resorted to using the banned chemical agents in warfare.

On Thursday, ISIS fired 19 chemical rockets on Peshmerga forces in the city of Sinjar, Northern Iraq. The Iraqi Kurds recently retook the city from ISIS, cutting off ISIS supply lines to Mosul, another major city still held by the jihadist group.

Although the city has been freed from the clutches of ISIS, the evacuees still refused to return to their homes because of the continuing threat of ISIS attacks.

"This is why we cannot come back," one man told a CBN News crew. "ISIS is still close enough to kill us in many ways. And now they are using chemical weapons. Please help us push them back far away, please stop them."

CBN News Military Correspondent Chuck Holton recently drove to northern Iraq on the front lines to monitor the fighting up close.

Holton said from time to time ISIS fighters fire mortar rounds into the city. He said when a mortar is fired, they've got about 15 seconds before finding out where it's going to land.

"It's kind of a scary feeling because you don't have any control over where they are going to land," he said. "And if they land right here, it's game over."

Meanwhile on the Syrian battlefront, ISIS forces launched a surprise attack on the town of Tal Abyad near the Turkish border on Saturday even as U.S. and Russian-brokered cease-fire brought relative calm to parts of war-torn Syria for the first time in years, CBS News reported.

ISIS, which is not a signatory to the cease-fire, launched several attacks after the truce went into effect, including a brazen offensive on the northern town of Tal Abyad on the border with Turkey and at least one suicide bombing in central Syria.

The cease-fire went into effect across Syria at midnight. Despite numerous breaches, the truce still marked the most ambitious international effort yet to ease the conflict, which has killed more than 250,000 people, wounded a million and created Europe's worst refugee crisis since World War II.

In addition to ISIS, the truce also excludes al Qaeda's branch in Syria, known as al Nusra, which is also considered a terrorist organisation by the United Nations.

A top military official in Moscow said Russia has grounded its warplanes in Syria to help secure the cease-fire.