UN secretary-general Antonio Guterres has said the world owes impoverished Pakistan “massive” help recovering from devastating floods because other nations have contributed more to the climate change thought to have triggered the deluge.

Months of monsoons and flooding have killed 1,391 people and affected 3.3 million in the Islamic nation.

Half a million people there have become homeless.

Planeloads of aid from the US, the United Arab Emirates and other countries have begun arriving.

But there is more to be done, Mr Guterres said.

Nature, the UN chief said in Islamabad, has attacked Pakistan, which contributes less than 1% of global emissions, according to multiple experts.

Nations “who are more responsible for climate change… should have faced this challenge”, Mr Guterres said, seated next to Pakistani Prime Minister Shehbaz Sharif.

“We are heading into a disaster,” Mr Guterres added.

“We have waged war on nature and nature is tracking back and striking back in a devastating way. Today in Pakistan, tomorrow in any of your countries.”

The UN secretary-general’s trip comes less than two weeks after he appealed for 160 million dollars (£137 million) in emergency funding to help those affected by the monsoon rains and floods that Pakistan says have caused at least 10 billion dollars (£8.6 billion) in damage.

International aid is arriving, including the first planeload of what the US has pledged will be 30 million dollars (£25 million) in assistance.

Earlier, the UN chief took to Twitter, saying: “I appeal for massive support from the international community as Pakistan responds to this climate catastrophe.”

Mr Guterres said on Friday that other nations contributing to climate change are obligated to reduce emissions and help Pakistan.

He assured Mr Sharif that his voice was “entirely at the service of the Pakistani government and the Pakistani people” and that “the entire UN system is at the service of Pakistan”.

The UN chief said “Pakistan has not contributed in a meaningful way to climate change, the level of emissions in this country is relatively low. But Pakistan is one of the most dramatically impacted countries by climate change”.

Later, Mr Guterres directed his words to the “international community”, saying that by some estimates Pakistan needs about 30 billion dollars (£25 billion) to recover.

So far, UN agencies and several countries have sent nearly 60 planeloads of aid, and authorities say the United Arab Emirates is one of the most generous contributors, as it has sent so far 26 flights carrying aid or flood victims.

On Friday, USAID administrator Samantha Power met with Pakistan’s foreign minister Bilawal Bhutto Zardari in Islamabad.

The floods have touched all of Pakistan, including heritage sites such as Mohenjo Daro, a Unesco World Heritage Site considered one of the best-preserved ancient urban settlements in South Asia.

The civilisation dates back 4,500 years, coinciding with those of ancient Egypt and Mesopotamia.

The UN heritage agency on Thursday announced it would send 350,000 dollars (£304,000) to help recover flood-damaged cultural heritage sites.

Since June, heavy rains and floods have added new burdens to cash-strapped Pakistan and highlighted the disproportionate effect of climate change on impoverished populations.

Experts say Pakistan is responsible for only 0.4% of the world’s historic emissions blamed for climate change.

The US is responsible for 21.5%, China for 16.5% and the EU 15%.

The floods in Pakistan have also injured 12,722 people, destroyed thousands of kilometres of roads, toppled bridges and damaged schools and hospitals, according to the National Disaster Management Agency.