At least eight other people were wounded in the shooting rampage in Kawit township, about 16 kilometers (10 miles) south of Manila, said Cavite provincial Gov. Jonvic Remulla. He identified the gunman as Ronald Bae, whose age was unclear, though officials said he appeared to be in his 30s or 40s. Bae was killed in a shootout with responding police.
It was not immediately clear why Bae went on the rampage, Remulla said.
The governor, however, said that Bae left his Kawit neighborhood about a year ago after he lost an election for village chairman, and returned on Monday due to a "marital problem" with his wife, whom he had left in northern Pampanga province before New Year's.
Remulla said that the caretaker of Bae's house in Kawit was seen reloading the gunman's weapon, and that police were looking for him.
The governor said Bae and several friends were on a "drug and alcohol binge" from Monday to Friday, drinking alcohol and taking methamphetamine. Bae left a store where he and his friends were drinking but later returned with his caretaker and began the shooting spree in the surrounding neighborhood, Remulla said.
He said Bae first killed a man who lived across the street from his house. He also killed the man's dog.
"He just shot at anyone he saw," Remulla said. "You could see that these were really acts of a madman. He even killed the dog."
Bae then shot and killed the 7-year-old girl inside her home and wounded her two younger siblings - her 2-year-old sister and 4-year-old brother, who is one of the gunman's godsons.
The two siblings who survived were in critical condition at a hospital. No details were immediately available on the condition of the other victims who were wounded.
The pregnant woman died after being shot in the stomach, Remulla said. Her 6-month-old fetus also died.
Edwin Lacorte, an uncle of the three children who were shot, said he could hear them screaming from his home nearby.
"I could not do anything," he said. "I could hear them screaming and I heard the shots."
Lacorte said that he later saw bullet-riddled cushions that the children had apparently used to protect themselves during the attack.
"It must have been the eldest who covered them with the cushions," he said.
Lacorte said he was at home during the rampage, and that as Bae closed in on his house, he fled with his wife and their four children, two grandchildren and three nieces.He said had he not been home, "my family would have been wiped out."
Lacorte said he and his family crouched as they ran from the gunman through the muddy former fishpond behind their house."He was shooting at us as we were running," he said.