Image copyright Carlo Gabuco

The Philippines is in the midst of a brutal war on drugs sanctioned by the controversial President Rodrigo Duterte, which has seen almost 2,000 killings in a matter of weeks. The BBC's Jonathan Head explores the country's dark underbelly of dealers and assassins through the story of one woman trapped in a chilling predicament.

When you meet an assassin who has killed six people, you don't expect to encounter a diminutive, nervous young woman carrying a baby.

"My first job was two years ago in this province nearby. I felt really scared and nervous because it was my first time."

Image copyright Carlo Gabuco

Maria, not her real name, now carries out contract killings as part of the government-sanctioned war on drugs.

She is part of a hit team that includes three women, who are valued because they can get close to their victims without arousing the same suspicion a man would.

Since President Duterte was elected, and urged citizens and police to kill drug dealers who resisted arrest, Maria has killed five more people, shooting them all in the head.

Media playback is unsupported on your device Media caption Inside Manila's drug war: Female assassin's story

I asked her who gave the orders for these assassinations: "Our boss, the police officer," she said.

On the very afternoon we met, she and her husband had been told their safe house had been exposed. They were moving in a hurry.

This controversial drug war has brought her more work, but more risk too. She described how it began when her husband was commissioned to kill a debtor by a policeman - one who was also a drug pusher.

Image copyright Carlo Gabuco

"My husband was ordered to kill people who had not paid what they owed."

This turned into a regular commission for her husband until a more challenging situation cropped up.

"One time, they needed a woman... my husband tapped me to do the job. When I saw the man I was supposed to kill, I got near him and I shot him. "

Image copyright Reuters Image caption President Duterte came to power promising to crack down on crime and drugs

Maria and her husband come from an impoverished neighbourhood of Manila and had no regular income before agreeing to become contract killers. They earn up to 20,000 Philippines pesos ($430; £327) per hit, which is shared between three or four of them. That is a fortune for low-income Filipinos, but now it looks as if Maria has no way out.

Contract killing is nothing new in the Philippines. But the hit squads have never been as busy as they are now. President Duterte has sent out an unambiguous message.

Ahead of his election, he promised to kill 100,000 criminals in his first six months in office.

And he has warned drug dealers in particular: "Do not destroy my country, because I will kill you."

Last weekend he reiterated that blunt view, as he defended the extrajudicial killings of suspected criminals.

"Do the lives of 10 of these criminals really matter? If I am the one facing all this grief, would 100 lives of these idiots mean anything to me?"

Media playback is unsupported on your device Media caption The BBC witnesses a drugs raid in one of Manila's biggest prisons

What has provoked the rough-tongued president to unleash this merciless campaign is the proliferation of the drug crystal meth or "shabu" as it is known in the Philippines. Cheap, easily made, and intensely addictive, it offers an instant high, an escape from the filth and drudgery of life in the slums, a hit to get labourers in gruelling jobs like truck-driving through their day.

What is Shabu?

Image copyright Reuters

Often called "ice" or "crystal meth" in the West, Shabu is the term used for a pure and potent form of amphetamine in the Philippines and other parts of Asia.

Shabu costs about 1,000 Philippines peso per gram ($22; £16)

It can be smoked, injected, snorted or dissolved in water

The Philippines is home to industrial-scale labs producing tonnes of the drug - which is then distributed throughout Asia.

Mr Duterte describes it as a pandemic, afflicting millions of his fellow citizens. It is also very profitable. He has listed 150 senior officials, officers and judges linked to the trade. Five police generals, he says, are kingpins of the business. But it is those at the lowest levels of the trade who are targeted by the death squads.

According to the police more than 1,900 people have been killed in drug-related incidents since he took office on 30 June. Of those, they say, 756 were killed by the police, all, they say, while resisting arrest. The remaining deaths are, officially, under investigation.

In practice most will remain unexplained. Nearly all those whose bloodied bodies are discovered every night in the slums of Manila and other cities are the poor - pedicab drivers, casual labourers, the unemployed. Often, found next to them are cardboard signs warning others not to get involved in drugs. This is a war being fought almost exclusively in the poorest parts of the country. People like Maria are used as its agents.

Duterte's war on drugs Since 1 July 1,900 drug deaths 10,153 drug dealers arrested

1,160 deaths still being investigated

756 suspects killed by police

300 officers suspected of involvement AFP

But it is a popular war. In Tondo, the shantytown area next to Manila port, most of the residents applaud the president's tough campaign. They blamed the "shabu" scourge for rising crime, and for destroying lives, although some worried that the campaign was getting out of hand, and that innocent victims were being caught up in it.

One of those being hunted by the death squads is Roger - again not his real name.

He became addicted to shabu as a young man, he says, while working as a casual labourer. Like many addicts he began dealing to support his habit, as it was a more comfortable job than labouring. He worked a lot with corrupt police officers, sometimes taking portions of the drug hauls they confiscated in raids to sell.

Image copyright JONATHAN HEAD

Now he is on the run, moving from place to place every few days to avoid being tracked down and killed.

"Every day, every hour, I cannot get the fear out of my chest. It's really tiring and scary to hide all the time. You don't know if the person right in front of you will inform on you, or if the one facing you might be a killer. It's hard to sleep at night. One small noise, I wake up. And the hardest part of all is I don't know who to trust, I don't know which direction to go every day, looking for a place to hide."

Image copyright Carlo Gabuco

He does feel guilt about his role in the trade of this destructive drug.

"I do truly believe that I have committed sins. Big time. I have done many awful things. I've wronged a lot people because they've become addicted, because I'm one of the many who sells them drugs. But what I can say is that not everyone who uses drugs is capable of committing those crimes, of stealing, and eventually killing. I'm also an addict but I don't kill. I'm an addict but I don't steal."

He has sent his children to live with his wife's family in the countryside, to try to stop them being exposed to the drug epidemic. He estimates that between 30% and 35% of people in his neighbourhood are addicts.

Image copyright Carlo Gabuco

So when President Duterte stated several times during his presidential campaign that he would kill drug dealers, throw their bodies into Manila Bay, did Roger not take that threat seriously?

"Yes, but I thought he would go after the big syndicates who manufacture the drugs, not the small time dealers like me. I wish I could turn the clock back. But it is too late for me. I cannot surrender, because if I do the police will probably kill me."

Image copyright Carlo Gabuco

Maria also regrets the choice she has made.

"I feel guilty and it is hard on my nerves. I don't want the families of those I have killed to come after me."

She worries about what her children will think. "I do not want them to come back at us and say that they got to live because we killed for money." Already her older boy asks questions about how she and her husband earn so much.

She has one more hit, one more contract to fulfill, and would like that to be her last. But her boss has threatened to kill anyone who leaves the team. She feels trapped. She asks her priest for forgiveness at confession in church, but does not dare to tell him what she does.

Image copyright Carlo Gabuco

Does she feel any justification carrying out President Duterte's campaign to terrorise the drug trade into submission?

"We only talk about the mission, how to carry it out," she says. "When it is finished we never talk about it again."

But she wrings her hands as she speaks and keeps her eyes shut tight, pursued by thoughts she does not want to share.