At least one person has been shot dead as Thai government supporters and foes clashed for the first time in a week of demonstrations against the government of Prime Minister Yingluck Shinawatra.

Ten people were also injured, hospital sources told Al Jazeera. It was not immediately known who fired the shots.

The shooting in the capital, Bangkok, occurred after dark on Saturday night following scattered violence involving government opponents waylaying and beating several people they believed were going to a rally at a stadium of “Red Shirt'' government supporters.

Earlier on Saturday, protesters marched on the country’s two main telecommunications enterprises in Bangkok in an effort to paralyse the government.

They have for the past week occupied or besieged government offices in what they describe as a civil disobedience campaign. They have vowed to seize the prime minister's offices on Sunday.

A mix of royalists, southerners and the urban middle class, the government's opponents are collectively called the Yellow Shirt movement and are united by their dislike for Thaksin Shinawatra, the controversial former prime minister.

Thaksin, a one-time telecoms tycoon, was toppled in a military coup in 2006 and lives in self-imposed exile, but he is widely believed to be the real power behind the government of his younger sister Yingluck.

'Demolish the regime'

Protesters were demanding the removal of the "Thaksin regime" and the replacement of the government with an unelected "people's council".

Suthep Thaugsuban, the protest leader and a former Thai deputy prime minister, said the demonstrators remained "very upbeat".

"If we demolish the Thaksin regime ... we will set up a people's council, which will come from people from every sector," he said.

Reporting from the city's centre, Al Jazeera's Scott Heidler said the government had earlier made an effort to keep the Red Shirts away from the Yellow Shirts.

Turnout was expected to surge over the weekend as organisers seek a final push before celebrations for Thai King Bhumibol Adulyadej's birthday on December 5, which is traditionally marked in an atmosphere of calm and respect.

The protest organisers have declared Sunday a "day of victory", with plans to gather near the heavily guarded Government House, besiege more important buildings - even Bangkok's zoo - and to tighten their blockade of government ministries.

Several challenges

Prime Minister Yingluck has faced down several legal and institutional challenges in recent weeks from the opposition Democrat Party, many of whose members have taken to the streets with the anti-government protesters.

The protests escalated after her ruling Puea Thai party tried to introduce an amnesty that could have allowed Thaksin's return, and have continued despite the Senate's rejection of the bill.

Puea Thai came to power in 2011 elections on a wave of Thaksin support, after a bloody 2010 military crackdown on Red Shirt protests under the then Democrat-led government left some 90 people dead.

Thaksin is adored by many of the country's rural and urban working class but hated by many southerners, middle-class Thais and the Bangkok elite, who see him as corrupt and a threat to the monarchy.

In a statement released on Friday, Prayuth Chan-O-Cha, the Thai army chief, urged protesters to respect "the democratic process under the law", urging people to come together.