First it was drug dealers, now smokers are in the crosshairs of the Philippine president.

People who smoke in public could face a four-month prison sentence or a $100 fine after a decree passed by Rodrigo Duterte aims to clamp down on those who light up.

The law which was announced on Thursday (18 May) will forbid tobacco use, as well as e-cigarettes, in all public spaces including pavements.

Under the law, designated smoking areas no bigger than 10 sq m must be at least 10m from building entrances, Reuters reported.

The president, a former smoker himself, instituted the ban because he said people should be able to enjoy clean air.

However as around 17 million people in the country smoke, or a third of the adult population, including half of all men, it may be difficult to enforce.

There were similar smoking restrictions imposed in Davao City where he was mayor for more than two decades, the Telegraph reported.

Duterte continues to face criticism over his anti-drug campaign which Human Rights Watch has said has led to the killing of 7,000 suspected drug users and dealers since he took office in June 2016.

The EU has warned that Duterte's drug campaign could mean his country would lose tariff-free exports to Europe.

Philippines president Rodrigo Duterte warns that North Korea 'wants to end the world'
Philippines president Rodrigo Duterte