He made the remarks during a press conference in Baku along with Azerbaijani President Ilham Aliyev, whose energy-rich country is set to host the COP29 UN Climate Change Conference in November.

Praising Azerbaijan for its "important role in delivering (natural) gas to key NATO allies," Stoltenberg said "the challenge is that the world needs energy, but at the same time we need to fight global warming."

"We need to reconcile the need for energy and environment," he said, adding that "climate change matters for security, matters for NATO."

"Climate change is a crisis multiplier, and we see the effects of climate change all over the world."

Stoltenberg also hailed Azerbaijan for investing in alternative energies, stressing the country's "great potential" as a supplier of hydropower and solar power to the European markets.

The decision to hold a climate summit in oil-and-gas-producer Azerbaijan has been criticised by environmental groups.

But the tightly controlled Caspian nation is seeking to change its reputation as a polluting authoritarian state.

Aliyev said that while his country is a "pan-European gas supplier" it has an ambitious green transition agenda.

He said Azerbaijan's selection as a host of COP 29 on November 11-24 was a "sign of recognition of our efforts on green transition."

2024 will be the second year in a row that the COP29 will be hosted by an oil giant, with the 2023 conference held in the United Arab Emirates.

Adding to the controversy, the presidency of the conference has been entrusted to Mukhtar Babayev, a former executive of Azerbaijan's state oil company, SOCAR.