The armed border clashes between Thailand and Cambodia entered the 4th day on Sunday.

According to a statement issued by the Thai Foreign Ministry, Richa Suksuwanon, deputy spokesperson of the Thai army, said that the first shots were fired into Thai territory in several areas, including a civilian house, by Cambodia early Sunday.

Meanwhile, Cambodian Defense Ministry's Undersecretary of State and Spokesperson, Lieutenant General Maly Socheata, said that from 2:00 a.m. to 6:00 a.m. local time on Sunday, the Thai army fired artillery at various locations in the Preah Vihear and Oddar Meanchey provinces.

"Our forces have fought back actively and vigorously to defend our territorial sovereignty," she said.

Since the armed clashes between Cambodian and Thai soldiers over disputed border areas broke out on Thursday, more than 30 people have been killed from both sides, and more than 100,000 people have been evacuated to safe areas, according to figures provided by the two countries.

Both sides have accused each other of violating international law and opening fire first.