WASHINGTON (AP) — A simmering division between the president and environmental groups is starting to boil over.

At issue is the president's embrace of increased oil and gas production. Eighteen environmental groups sent letter before Obama's State of the Union speech saying the policy conflicts with his global warming goals.

But in his speech Tuesday, Obama said his all-of-the-above strategy is working.

The rift between Obama and some of his staunchest supporters has existed for months.

White House officials knew since last May that a letter objecting to their energy policy was in the works. But they urged environmental groups to wait until after Obama's speech last June on climate change, hoping it would change their minds.