Suspected insurgents staged the most deadly co-ordinated attacks in years in Thailand's restive south, killing 14 people and wounding 340 with car bombs on Saturday.

The attacks targeted weekend shoppers and a high-rise hotel frequented by foreign tourists.

A first batch of explosives planted inside a parked pickup truck ripped through an area of restaurants and shops in a busy area of Yala city, a main commercial hub of Thailand's southern provinces, district police chief Col. Kritsada Kaewchandee said.

About 20 minutes later, just as onlookers gathered at the blast site, a second car bomb exploded, causing the majority of casualties. Eleven people were killed and 110 wounded by the blasts.

Casualty count tops 5,000 since 2004

More than 5,000 people have been killed in Thailand's three southernmost provinces — Narathiwat, Pattani and Yala — since an Islamist insurgency flared in January 2004.

Most attacks are small-scale bombings or drive-by shootings that target soldiers, police and symbols of authority, but suspected insurgents have also staged large attacks in commercial areas.

Separately on the weekend, a blast occurred at a high-rise hotel in the city of Hat Yai, in the nearby province of Songkhla.

The midday explosion at the 405-room Lee Gardens Plaza Hotel, where throngs of Malaysian and Singaporean tourists spend their weekends, killed three people and caused about 230 injuries, mostly from smoke inhalation, police Lt. Puwadon Wiriyawarangkun said.

Authorities found a severely damaged sedan and a hole created by the explosion's impact in the hotel's basement parkade.

Regional police chief Lt. Gen. Jakthip Chaijinda said the Hat Yai incident "is likely related to what happened in Yala and might have been plotted by the same group of insurgents."

The same hotel was targeted in 2006, when four people, including a Canadian man, were killed by six bombs that had been planted on Hat Yai's main street.

Thailand annexed Muslim-majority area

In another incident Saturday, suspected militants detonated a motorcycle bomb 50 metres from a local police station in Pattani province's Mae Lan district, wounding one police officer, according to police Col. Tharet Kaewla-eiad.

The choreographed strikes follow a series of incidents last October, in which suspected militants staged attacks at more than 30 spots across Yala city, killing three people and injuring more than 50.

Thai authorities have imposed a state of emergency since 2005 that gives security forces special powers to arrest and detain suspects in the three restive provinces. But the decree and a massive security presence have failed to curb the violence, and little is known about the militants or their goals.

The insurgents have made no public pronouncements but are thought to be fighting for an independent Muslim state. The area used to be an Islamic sultanate until it was annexed by Thailand in the early 20th century.

Yala, Narathiwat and Pattani are the only Muslim-dominated provinces in the predominantly Buddhist country. Muslims in the area have long complained of discrimination by the central government.