London, UK - The US on Thursday came out in opposition to policies designed to phase out fossil fuels and take meaningful action on climate change, labeling them "harmful and dangerous."

US Acting Assistant Secretary of Energy for International Affairs Tommy Joyce used his appearance at the Summit on the Future of Energy Security in London to attack the effort to combat climate change.

The summit is being held over two days with a focus on discussing the role of renewable energy sources and the gradual shift away from fossil fuels in creating better energy security.

"Some want to regulate every form of energy besides the so-called renewables, completely out of existence," Joyce claimed. "We oppose these harmful and dangerous policies. This is not energy security."

His comments contrasted with a more moderate message from the executive director of the International Energy Agency (IEA), who hosted the summit.

"Every economy has its own pathway for energy. We should understand and respect it," said IEA director Fatih Birol. "Oil and gas are key parts of our energy mix, and they will remain as part of the energy mix in years to come."

A number of energy ministers from across Europe and beyond gathered in London for the summit, while the US was only represented by minor officials like Joyce.

The event drew hundreds of protestors who railed against new oil and gas drilling in UK waters, many holding up giant eyeballs and signs reading "No new oil and gas."

The UK's Energy Secretary Ed Miliband used the occasion to welcome "low carbon energy" as playing "a critical role in delivering energy security."

"As long as energy can be weaponized against us, our countries and our citizens are vulnerable and exposed," Miliband said.