Islamabad, Aug 20 (IANS): Millions of internet users in Pakistan lost access after deadly flooding triggered by heavy monsoon rainfall caused extensive damage to a critical network.

Services offered by all operators throughout the nation's central and northern regions were unavailable as of Friday, Pakistan's Telecommunication Authority (PTA) said in a statement.

Several cities lost connectivity including the capital Islamabad, in an outage that also rendered the emergency telephone helplines of hospitals and rescue departments inaccessible, reports dpa news agency.

The Pakistan Telecommunication Company Limited (PTCL), the country's largest operator, said floods had caused damage to its fiber optics, leading to the disruption of data networks.

Around 50 million users were facing either the complete outage or a slow connectivity, the telecom authority said.

Pakistan, a South Asian nation among the top countries facing the impact of climate change, is struggling amid massive flooding triggered by heavy monsoon rains since mid-June,

The floods have killed 674 people and damaged more than 75,000 houses so far, according to the national disaster agency, warning against more rainfall in the coming days.