A Syrian rebel group in the country's northwest said it came under attack from regime ground forces at 4 a.m. (0200 GMT) on Saturday in what it called a breach of a cessation of hostilities plan that came into effect at midnight.Three fighters from the rebel First Coastal Division were killed while repelling the attack in the Jabal Turkman area near the Turkish border in Latakia province, Fadi Ahmad, the group's spokesman, told Reuters.The Syrian military could not immediately be reached for comment.Elsewhere, the Syrian rebel group Jaish al-Islam said Assad regime forces dropped two barrel bombs and opened fire on its positions during several violations of a cessation of hostilities agreement in the Eastern Ghouta near Damascus on Saturday.Citing field reports from the group's commanders, Jaish al-Islam spokesman Islam Alloush told Reuters that in one incident government forces trying to advance "were dealt with with machine guns". Meanwhile, a ceasefire in Syria was largely holding on Saturday, hours after the deal brokered by Russia and the United States went into effect, a monitoring group said.The Britain-based Syrian Observatory for Human Rights said fighting between regime forces and rebels in the north-western province of Latakia was continuing despite the ceasefire, which the Syrian government and 97 opposition groups have agreed to abide by.Syrian state television reported that two people died in a car bomb explosion in the central government-held town of Salamiyeh. No one has claimed responsibility for the attack.The Syrian regime has said it will respect the agreement drawn up by Russia and the United States, but has said it will continue to fight the al Qaeda-linked Nusra Front and Daesh which are not covered by the deal.