MANILA - Following its ban on bottled drinks, the Metro Rail Transit released Thursday a list of liquids and other items allowed inside its stations.

In a statement, the transportation department asked the public for deeper understanding as it implements its new security policy.

"As we have stressed earlier, we have banned bottled drinks, water and any liquid substance as these can be mixed to form a liquid bomb," it said.

It cited how nitroglycerin, an explosive liquid that is also a component of drugs for heart conditions, could be easily hidden in seemingly harmless bottles.

"Nitroglycerin is oily and clear, so if it is poured in an opaque lotion bottle, no one would know what is inside. Because it is clear and oily, nitroglycerin would be easy to conceal in lotion or shampoo bottles. Nitroglycerin's inherent instability would make this bottle very dangerous for you to carry around," it added.

The agency said some liquids such as breast milk in bottles and baby formula, and all prescription and over-the-counter medication, will be allowed "upon validation and approval of our security personnel, and police officers in our stations."

Items that have been held by security personnel, including items which were previously prohibited, may be claimed by their respective owners from the station supervisor upon verification through presentation of proper identification.

Below is the full list of allowed items:

- Baby formula / breast milk in bottles, if the passenger is travelling with a baby or small child;

- Drinking water to be used by the baby or small child;

- All prescription and over-the-counter medications;

- Liquids including water, juice or liquid nutrition or gels for passenger with a disability or life condition;

- Life-support and life-sustaining liquids such as bone marrow, blood products, and transplant organs;

- Items used to augment the body and for medical and cosmetics reasons such as mastectomy products, prosthetic breast, bras or shells containing gels, saline solution, or other liquids; and

- Gels or frozen liquids needed to cool disability or medical-related items used by persons with disabilities or medical conditions.

The transportation department banned all bottled drinks in train stations in late January following twin blasts in Jolo, Sulu, which left 22 dead and more than 100 hurt.