A Thai police officer talks with anti-government protesters
Thailand has been gripped by a paralysing political crisis since Prime Minister Thaksin Shinawatra was ousted from office in a military coup in September 2006.
When Democrat Party leader Abhisit Vejjajiva was chosen as prime minister in December 2008, some Thais hoped the protests had finally come to an end.
But the political schism is far from over. In March 2010 the pro-Thaksin red-shirts launched new protests aimed at bringing the government down.
Two months on, the protesters were evicted by the army from their fortified encampment in Bangkok's city centre.
A week of clashes left at least 50 people dead, most of them protesters.
Analysts and some participants say the problem goes far beyond Mr Thaksin, and is about how much say ordinary people are allowed to have in the formation of their government.
Who are the pro-Thaksin protesters?
Many of the protesters come from Thailand's rural north and northeast. They benefited from the populist policies Mr Thaksin framed during his five years in power - such as on health and education - and many of them want him back.
Mr Thaksin is out of the country but speaks to supporters via video link
Others are urban intellectuals who want to see more democracy and less military influence in the country.
These various constituencies make up the anti-government United Front for Democracy Against Dictatorship (UDD), and are known for wearing distinctive red shirts.
The red-shirts say Prime Minister Abhisit Vejjajiva came to power illegitimately and is a puppet of the military. They want Mr Abhisit to resign and call fresh elections.
During the recent protests in Bangkok it has become clear that a hard-line group exists within the red-shirts. It is not clear to what extent the more moderate red-shirt leaders have control over this group.
What have the red-shirts been up to?
In April 2009 the red-shirts forced the cancellation of a summit of the Association of South-East Asian Nations (Asean). They stormed the venue in the seaside resort of Pattaya, causing huge embarrassment to the government.
A day later, tens of thousands of protesters broke into the interior ministry, and camped around Government House; a clampdown resulted in the deaths of two people.
The red-shirts went home, only to return almost a year later. This time they came in force, with tens of thousands joining the first rally in Bangkok. They vowed not to leave until the government stood down.
From their first camp around Government House, they moved into Bangkok's shopping hub. Over the course of a month, they stormed parliament, the Election Commission and a key satellite TV base.
On 10 April an attempt by the military to clear them from one of their camps turned violent. At least 25 people were killed, including at least five soldiers.
When Mr Abhisit offered polls on 14 November it appeared as if a deal could be in the offing. But none was reached, because of divisions over holding the deputy prime minister accountable for the 10 April violence.
On 13 May the Thai military moved to seal off the protest camp. Clashes then erupted when a renegade general who backed the protesters was shot.
Deadly clashed between troops and protesters in several areas bordering the protest camp followed. More than 30 people have been killed.
On 17 May the government gave a deadline of 1500 (0800 GMT) for protesters to leave their protest area. When the army finally acted on 19 May, some of the main red-shirt leaders told their followers to give up the protest and go home.
Most left the protest camp but others fought the army. A number of buildings, including a major shopping centre, government buildings and the stock exchange, were set on fire, causing serious damage.
Who are the anti-Thaksin protesters?
The opponents of Mr Thaksin call themselves the Peoples' Alliance for Democracy (PAD) and wear yellow shirts.
They are a loose grouping of royalists, businessmen and the urban middle class, led by media mogul Sondhi Limthongkul and Chamlong Srimuang, a former general with close ties to the king's most senior adviser, Gen Prem Tinsulanonda.
The PAD protesters helped bring down two pro-Thaksin governments
The PAD was instrumental in setting the scene for the military coup which removed Mr Thaksin from office in 2006.
And months after his allies were re-elected in the first post-coup polls, they took over Government House for three months and engineered a week-long siege of Bangkok's main airports in December 2008, crippling the country's vital tourism industry.
Together with several court rulings against Mr Thaksin's political parties, they are credited with bringing down two governments of his allies - firstly the administration of Samak Sundaravej and then that of Mr Thaksin's brother-in-law Somchai Wongsawat.
Once the Democrats were in power, the yellow-shirts went quiet. But after a month of red-shirt demonstrations in Bangkok, they intervened. On 18 April 2010, they gave the government a week to end the political crisis or face mass action.
They have since called on Mr Abhisit to resign, but the promised demonstrations have not materialised.
How did Mr Abhisit become prime minister?
Amid the turmoil of the airport blockade in December 2008, a Constitutional Court ruled that the then ruling pro-Thaksin party was guilty of electoral fraud and barred its leaders from politics for five years.
A few Thaksin loyalists were persuaded to change sides to join a coalition led by the other main party, the Democrats.
This enabled Democrat leader Abhisit Vejjajiva to become the next prime minister, with military backing, without calling elections.
Where is Mr Thaksin now?
Mr Thaksin describes himself as a citizen of the world, and he is often in Dubai, China, the UK or Hong Kong.
If he did come back to Thailand, he would face two years in jail after being found guilty in absentia in a conflict of interest case.
His long-term aims are unclear. In the past he has said he will not re-enter politics, but he has also said he is needed to lead Thailand out of the economic crisis.
He remains actively involved in Thai politics, often appearing via video-link at red-shirt rallies.
Where do Thai politics go from here?
The impression given of the red-shirts in pro-government media is of a Thaksin-fixated rabble, prone to violence.
But red-shirt leaders say their movement is about much more than one man and his money; they say the movement is about more profound social change.
They say that every vote should count, and that Thailand should break out of a pattern of military intervention supporting an elite bureaucratic system.
As the recent violence on the streets of Bangkok shows, divisions in Thai society run very deep.
At the moment neither the protesters nor the government appear in the mood to compromise - and while the red-shirts have gone home, some say they will be back.