The Pentagon is readying for a more intense and longer attacks on Syria than originally planned, set to last three days, a report said on Sunday.

Pentagon planners now aim to unleash a heavy barrage of missile strikes to be followed swiftly by additional attacks on targets that may have been missed or remain standing after the initial launch, the Los Angeles Times reported quoting US officials as saying.
Two US officers said the White House had asked for an expanded target list to include “many more” than the initial list of around 50 targets.

The move is part of an effort to obtain additional firepower to damage Syrian President Bashar al-Assad's dispersed forces.

War planners are now considering using Air Force bombers, as well as five US missile destroyers currently patrolling the eastern Mediterranean Sea, to launch cruise missiles and air-to-surface missiles from far out of range of Syrian air defences, according to the report.

The USS Nimitz aircraft carrier strike group with one cruiser and three destroyers positioned in the Read Sea can also fire cruise missiles at Syria.

"There will be several volleys and an assessment after each volley, but all within 72 hours and a clear indication when we are done," an officer familiar with the planning told the Times.

The intensified military planning comes as US President Barack Obama prepares to personally make his case to the American people and further press reluctant lawmakers on the need for action after Assad allegedly used chemical weapons on his own people last month.