Fears of civil conflict are mounting, with rival groups of supporters gathering in or around Bangkok.

Three people have died and scores were wounded in a grenade attack and drive-by shooting on an anti-government protest camp at the landmark Democracy Monument earlier today.

The government has downgraded its tourism prediction for 2014 from 28.4 million visitors to 26.3 million, blaming the unresolved political crisis for putting off visitors.

Sukree Sithivanich, of the Tourism Authority of Thailand, claimed the fall in numbers was not due to waning interest from European holidaymakers however.

Visits by European tourists were actually up by 7.63 per cent and Americans up by 0.48 per cent, he said in a report for the Thai PBS news service.

Thai election authorities called for polls scheduled for July to be postponed because of the unrest and General Prayut Chan-O-Cha, chief of the Thai army, warned today that his troops “may use force” to quell the violence.

The Foreign Office has warned that the situation is unpredictable and that further protests are expected.

A map produced by Richard Barrow, a resident travel blogger, has been updated to show where the incidents took place and where protestors are congregating around the city .

The main protest site is now at Ratchadamnoen Avenue, according to the Foreign Office, with a smaller protest site at the government complex at Chaeng Watthana and sporadic rallies to government offices and private companies.

“There have been indiscriminate attacks involving weapons and explosives at protest sites and at protest marches”, it advised travellers. “Attacks have taken place during the daytime and at night.

“You should take extra care and avoid all protests, political gatherings, demonstrations and marches. Monitor local news and social media for developments.”

At least 27 people have been killed and hundreds wounded since the protest campaign began in November.

Photo Credit: Member of the pro-government "red shirt" group holds an umbrella during a rally in Nakhon Pathom province. Reuters