The New Nation - Internet Edition

AFP, Bangkok

Grenade attacks targeting Thai anti-government protesters injured at least 51 people Sunday, stoking tensions as police struggled to end a paralysing blockade of Bangkok's airports.

The blasts came hours before thousands of supporters of the kingdom's embattled administration were due to hold their own mass rally in the centre of the capital, creating another potential flashpoint.

The five-day outbreak of civil unrest has caused mounting concern among foreign governments, with around 100,000 frustrated travellers trapped in the self-styled "Land of Smiles".

Police have held off launching an assault on the protesters occupying two Bangkok airports amid fears of a repeat of political violence that left two people dead last month, and concerns that more bloodshed could spark a coup.

In the latest violence , attackers lobbed a grenade at Government House, the prime minister's cabinet offices which the People's Alliance for Democracy (PAD) occupied in August. Emergency services said 49 people were wounded.

"Whatever happens, we will fight, we will not step back," senior PAD leader and retired general Chamlong Srimuang later told reporters at the site.

Hours later, a blast hit outside the small domestic Don Mueang airport, injuring two passers-by, police said. A grenade was also found at the offices of a party in the ruling coalition but did not go off.