The White House warned US lawmakers Tuesday that tightening sanctions on Iran could box America into a "march to war" and derail a diplomatic push to reach an agreement with Tehran on its nuclear program.

The White House warned US lawmakers Tuesday that tightening sanctions on Iran could box America into a "march to war" and derail a diplomatic push to reach an agreement with Tehran on its nuclear program.

The warning marked a significant toughening of President Barack Obama's stance towards skeptical US lawmakers as he prepares to resume high-stakes nuclear diplomacy with Iran later this month.

"The American people do not want a march to war," White House spokesman Jay Carney told reporters.

Carney said Americans "justifiably and understandably prefer a peaceful solution."

"The alternative is military action," Carney warned.

Last week intense negotiations between Iran and six world powers failed to reach a deal regarding Tehran's nuclear program.

A new round of nuclear talks is set on November 20 amid optimistic statements by several international officials pertaining the possibility of reaching a deal.