The United States hopes India will reverse its ban on wheat exports, Washington's top diplomat to the United Nations said Monday, warning the move would worsen global shortages of the commodity.

"We're encouraging countries not to restrict exports because we think any restrictions on exports will exacerbate the food shortages," Linda Thomas-Greenfield said during a ministerial gathering on food security ahead of a meeting of the UN Security Council.

The UN meeting -- to be chaired by US Secretary of State Antony Blinken -- will include Vellamvelly Muraleedharan, India's minister of state for external affairs. 

India holds a non-permanent seat on the UN Security Council.

"We hope that (India) can, as they hear the concerns being raised by other countries, that they would reconsider that position," Thomas-Greenfield said.

India, the world's second-largest producer of wheat, on Saturday announced it would ban exports without special authorisation from the government in the face of falling production caused primarily by an extreme heatwave. 

New Delhi -- which had previously pledged to supply wheat to countries once dependent on exports from Ukraine -- said it wanted to ensure "food security" for India's 1.4 billion people.

Blinken is on Wednesday set to hold another UN meeting also related to food security.

That session aims to "bring countries together to look at what countries might be able to help fill the gap" in wheat supplies caused by Russia's invasion of Ukraine -- two major exporters of the commodity, said Thomas-Greenfield.

The talks would also identify "countries who need the support from countries who can fill the gap," she added.

The United States could be included in these countries, she said, adding that discussions were already underway with American farmers on the topic.

Wheat prices hit a record high in the European market Monday in the wake of India's decision.

Wheat-laden trucks, ships stranded at Indian port

Hundreds of thousands of tonnes of wheat were stranded at a major port in India on Tuesday after New Delhi's surprise ban on exports over inflation and food security worries.

India, the world's second-largest grower of wheat, last week ordered that traders could not enter into new export deals without government approval.

The snap announcement has led to chaos at the port in Kandla, in Gujarat, where about 4,000 trucks are stuck in queues outside, according to the port operator.

Four ships partially loaded with about 80,000 tonnes of wheat are also docked at the facility.

Port officials said trucks that arrived before May 13, when the government announced the export ban, would be allowed to unload the grain onto ships waiting to take it to countries including Egypt and South Korea under prior agreements.

"However, those wheat-laden trucks that arrived at the port after May 13 will have to return with the commodity," said Om Prakash Dadlani, spokesman for operator Deendayal Port Trust.

The Gandhidham Chamber of Commerce estimated that about 400,000 tonnes of wheat from Punjab, Haryana, Madhya Pradesh and other wheat-growing states were stranded.

Between 500 and 700 warehouses near the port were "full of wheat for export", said Teja Kangad, president of the chamber.

The government should have given prior notice before announcing the ban, he said. 

"This has led to a chaotic situation where the truckers and traders are left uncertain of what will happen to the goods. Also, wheat being a perishable commodity, it can't be kept in the open for long," Kangad told AFP.

The wheat ban has drawn criticism from the Group of Seven nations worried about protectionism as inflation soars in the wake of the Ukraine war.

India had previously said it was ready to help fill some of the supply shortages caused by Russia's February invasion of Ukraine, which had accounted for 12 percent of global exports.

While India is a small exporter, its assurances of supplies from its large buffer stocks had provided some support to global prices and soothed fears of major shortages. 

India's wheat production has been hit by searing temperatures -- the country recorded its warmest March on record -- prompting the government to predict output would fall at least five percent this year from 109 million tonnes in 2021.  

Wheat prices surged to a record high on Monday, jumping to 435 euros ($453) per tonne as the European market opened.