Heavy rains across the Himalayan mountains have killed at least 36 people in the last 24 hours in India, 33 of them in one landslide near the Hindu shrine of Vaishno Devi on a pilgrim route in Indian-administered Jammu and Kashmir.

"The loss of lives due to a landslide on the route to the Shri Mata Vaishno Devi Temple is saddening. My thoughts are with the bereaved families. May the injured recover at the earliest," Prime Minister Narendra Modi said in response.

At least three more people were reported dead in the district of Dodi, while authorities were forced to open major dams to drain the rainwater, triggering flood alerts downstream for three rivers in neighboring Pakistan. 

Schools were closed in the contested border region, train services were halted for around a day and some highways to India were also rendered impassable.

Telecommunications services down, 612mm of rainfall in a few days

Omar Abdullah, the chief minister of Jammu and Kashmir, said officials were battling to restore "almost non-existent" telecommunications services in the area to facilitate rescue efforts and communication. 

Jitendra Singh, India's science and technology minister, said on social media that the "immediate priority is restoration of electricity, water supply and mobile services, for which the authorities have been working continuously overnight." 

Singh also said that while rain continued to fall in the worst-hit areas, its intensity had decreased. Schools in the region would remain closed on Wednesday, he said.

The Madhopur bridge over the Tawi river, of particular importance to India's ruling Hindu nationalist BJP because of its links to Shyama Prasad Mukherjee, commonly considered the party's founder, was among those to partly collapse overnight. 

"We had 612 millimeters (roughly 24 inches) rainfall in Jammu region since August 23 till today," Mukhtar Ahmad, director at the India Meteorological Department in the regional capital Srinagar, told Reuters. "This is 726% above-normal rainfall during this time of year. It is the highest rainfall in the region since 1950." 

Earlier in August, in Chiosti in Jammu and Kashmir, 65 people were killed in flash flooding after a sudden violent rainstorm.

India's monsoon season runs from June to September.

Pakistan issues flood warnings as India opens dams to relieve pressure

Authorities in Pakistan's eastern Punjab province called for the army to assist rescue and relief efforts. Officials said more than 150,000 people had been displaced and that rescuers moved more than 20,000 people from their homes in the outskirts of Lahore — Pakistan's second-largest city — overnight. 

India's government opened several dams to relieve pressure from the heavy rains, prompting Pakistan to issue an alert about potential flooding on three rivers flowing into its territory. 

Authorities said on Wednesday tha the Ravi, Chenab and Sutlej rivers in Pakistan had risen sharply as a result. 

Pakistan said India's most recent routine warning was the third of its kind in recent days amid the ongoing downpours.

As of Wednesday, Pakistan had logged 804 deaths during monsoon season, half of them in August.