With President Barack Obama scheduled to return to the campaign trail Thursday after a three-day break to focus on storm relief efforts, his campaign advisers dismissed signs that his Republican challenger was expanding the electoral battleground in states they had considered safe for the incumbent.

Two top campaign officials, in a conference call with reporters, argued that moves by Mitt Romney’s campaign and its allies to advertise in Minnesota, Pennsylvania and Michigan amounted to a “Hail Mary pass’’ to compete in sure-lose states because they do not have a path to winning 270 electoral votes in established battleground states like Ohio.