Bangkok: Thais marked King Bhumibol Adulyadej's 81st birthday on Friday in a solemn mood, concerned for the health of the aging monarch and worried as well over Thailand's debilitating political deadlock.

The king failed to deliver his annual birthday eve address at a time when many Thais had been looking to him to issue a call for unity after protests by People's Alliance for Democracy (PAD) activists shut down Bangkok's main airport for a week.

His speeches in the past three years have been nuanced and focused on the need for national unity, although his calls for clean government were widely read as a swipe at Thaksin Shinawatra, the populist prime minister ousted in a 2006 coup.

A palace statement on Friday said the king had had an intermittent fever since Wednesday but was being treated by doctors at his Bangkok palace. He had been put on a saline and glucose drip because a throat infection stopped him from eating.

Thailand's caretaker government canceled next Monday's special parliamentary session to choose a successor to Somchai Wongsawat, Thaksin's brother-in-law, who was convicted of vote fraud this week and banned from politics for five years.

Seen as semi-divine by many of Thailand's 65 million people, the king has intervened in politics three times during his six decades on the throne, variously favoring elected and military administrations.

The king spent several weeks in hospital last year with circulation problems and there are concerns about his health.

"If the king is very seriously ill, and we don't know that, it will put the succession issue at the forefront of people's minds," Craig Reynolds, a Thai historian at Australian National University, told Reuters.

The monarch has been thrust into the center of the fray by the PAD's persistent use of his name in their fight with Thaksin, whose popularity with rural voters, based on cheap healthcare and credit, upset Bangkok's old royal and military elite.

Source : Reuters