Less than a month before the state's presidential primary, Republican front-runner Donald Trump appears to be losing steam in Oklahoma, according to a poll released Tuesday.

Trump continues to lead an eight-candidate Republican field, with 30 percent of Oklahoma GOP voters reporting that they planned to vote for the New York billionaire, down from 35 percent in a poll released Jan. 23.

"Early on, Trump's been able to channel the anger and frustration felt among Republicans toward President Obama, but anger and frustration can only take you so far in a presidential race," said Bill Shapard, founder of SoonerPoll, an Oklahoma City-based firm that conducted the poll.

Meanwhile, Texas Sen. Ted Cruz held steady at 25 percent while Florida Sen. Marco Rubio surged, rising from 10 percent in late January to 21 percent this week.