Cambodia's strongman Prime Minister Hun Sen has vanquished virtually every foe in almost three decades in power but admits he has failed to overcome his smoking habit.

He pledged to do so Thursday at the inauguration of a dam in western Cambodia but admitted promising to do so at least 10 times before. There was once a time when he was rarely seen without one of his favored 555 brand clutched between his fingers.

The 61-year-old leader said the temptation seizes him mostly when he plays chess, an addiction equal to the one he has to nicotine.

Stopping smoking is hard, he acknowledged, but he said he is now down to three cigarettes a day at most and his home no longer reeks of tobacco. Just the night before, he said, he was searching for a smoke, "but luckily my grandson arrived."

His vows to stop date at least to 1997, when he said he would quit when his daughter graduated from school. Declarations to stop when all five of his children married, and later when he had grandchildren, also went up in smoke.

Hun Sen currently is facing the biggest challenge in many years to his authoritarian rule from opposition protests calling on him to resign and hold new elections. The opposition says elections last July were rigged.

Last month, Cambodia banned the import, sale and promotion of e-cigarettes and shisha tobacco, a favorite of hookah-using smokers. The Cambodian Anti-Drug Authority said , which emit containing nicotine, and shisha, flavored tobacco smoked through a water pipe, had been imported in increasing quantities and were becoming popular with young people, posing health and social problems.