US defence planners are preparing a range of land, sea and air military options in Libya in case Washington and its allies decide to intervene there, The New York Times reported late on Sunday.
The report came as Muammar Gaddafi's forces held off rebels near the dictator's hometown and recaptured a key city.
Untold numbers of "injured and dying" in the western city of Misrata meanwhile prompted a UN demand for urgent access to the civilian population repeatedly shelled by Gaddafi tanks on Sunday.
Citing unnamed administration officials, the newspaper said just simple use of signal-jamming aircraft in international airspace could muddle Libyan government communications with military units.
Administration officials said preparations for such an operation were under way, the report said.
The latest military force to draw within striking distance of Tripoli is the 26th Marine Expeditionary Unit aboard two amphibious assault ships, the Kearsarge and the Ponce, the paper noted.
The unit provides a complete air, sea and land force that can project its power quickly and across hundreds of miles, either from flat-decked ships in the Mediterranean Sea or onto a small beachhead on land, The Times said.
According to the report, another tactic would be to air-drop weapons and supplies to Libyan rebels.
Other options include inserting small special operations teams to assist the rebels, as was done in Afghanistan to topple the Taliban, the paper noted.
The teams are specially trained to turn ragtag rebel groups almost overnight into more effective fighters, with a modest infusion of know-how, equipment and leadership, it added.