NEW DELHI (REUTERS, AFP) - At least 25 people died after several houses in three Mumbai suburbs collapsed due to landslides caused by heavy rainfall, local officials said on Sunday (July 18).

Rainwater also inundated a water purification complex, disrupting supply "in most of the parts of Mumbai", a megacity of 20 million people, civic authorities said.

A falling tree demolished a wall in the eastern suburb of Chembur during Sunday's early hours, burying nearby residents, the National Disaster Response Force (NDRF) said.

Seventeen bodies had been recovered from the rubble, it added. Rescuers were searching the scene for more survivors and bodies.

"In the adjacent house, I saw a small girl who was trapped in the debris. She was shouting 'save me, save me'," Firoz Khan, who was caught up in the downpour in Chembur, told AFP.

"Her body was trapped in the mud. Somehow, I managed to pull her out. She had injuries in her legs. I narrowly survived this collapse."

Rescuers were seen using hands to dig the ground to retrieve bodies, local television showed, and the authorities said more could be trapped inside the debris.

Four of those injured were taken to a nearby hospital, officials said.

Local television news channels showed rescuers carrying the injured on makeshift stretchers using cloth, inside narrow lanes.

Within the last 24 hours authorities have so far reported 11 incidents of houses or walls collapsing in the Mumbai area, officials said.

In the suburb of Vikhroli in the city's northeast, six people were killed after a landslide hit five homes early Sunday, the NDRF added.

Building collapses are common during India's June-September monsoon season, with old and rickety structures buckling under days of non-stop rain.

In one of the neighbourhoods, about half a dozen huts located at the base of a hillock collapsed on top of one another, officials said.

Several areas in the city were waterlogged after heavy rainfall over the past 24 hours, and suburban train services were disrupted, crippling India's financial capital, where incidents of building collapses have become more common during the monsoon.

The Indian Meteorological Department said early Sunday that "moderate to heavy rain or thundershowers" were forecast for the next two days.

Prime Minister Narendra Modi tweeted his condolences and added that there would be financial compensation for victims' families.

Mumbai and the coast of India's industrial Maharashtra state are expected to receive heavy to very heavy rainfall in the next four days, the weather department said on Sunday.

The city's civic body did not say when the water supply was expected to be restored, but advised residents to boil the liquid before using it.

Torrential rain, especially during India's July-September monsoon, often triggers the collapse of buildings, especially older or illegally built structures.