Democratic presidential frontrunner Hillary Clinton on Monday rejected an invitation to take part in a final campaign debate against her rival Bernie Sanders, her campaign said.
"We have declined Fox News' invitation to participate in a debate in California," Clinton spokeswoman Jennifer Palmieri said in a statement, adding that the former secretary of state would concentrate on campaigning against presumptive Republican nominee Donald Trump instead.
"We believe that Hillary Clinton's time is best spent campaigning and meeting directly with voters across California and preparing for a general election campaign" in November, she added.
Sanders on Wednesday agreed to a debate in California, which is set to hold a potentially decisive primary on June 7 along with five other states.
The left-leaning Vermont senator responded to Clinton's decision on Monday saying in a statement that he was "disappointed but not surprised by Secretary Clinton's unwillingness to debate before the largest and most important primary in the presidential nominating process."
"Democracy, and respect for the voters of California, would suggest that there should be a vigorous debate in which the voters may determine whose ideas they support," he added.
Although Clinton is all but certain to win the Democratic Party's nomination, Sanders has dismissed calls to withdraw, saying a path for him remains open.
"Secretary Clinton may want to be not quite so presumptuous about thinking that she is a certain winner," he said in his statement. "In the last several weeks, the people of Indiana, West Virginia and Oregon have suggested otherwise."
However, a new poll released on Monday by local broadcaster KABC in Los Angeles showed Clinton's lead over Sanders in the state growing to 57 per cent against his 39 per cent.