Forces backing Libyan leader Muammar Gaddafi attacked rebels in the city of Benghazi on Saturday as international leaders met in Paris to discuss how to implement a UN resolution calling for a Gaddafi cease fire and authorizing military action to protect Libyan civilians.

Pro-Gaddafi tanks rolled into the town, as incoming artillery rounds landed in the city, witnesses told CNN. Civilians told the network that buildings had come under small arms fire.

Photos and images released Saturday showed a fighter jet falling from the sky and bursting into flames after crashing. The network could not confirm independently who the plane belonged to.

A doctor in Benghazi said 27 people were killed Saturday, according to the Associated Press. 

Meanwhile, international leaders were gathering in Paris on Saturday to decide what action to take, after a U.N. Resolution on Thursday approved military action to protect Libyan citizens.

Everything is ready (to act) but the decision is now a political one. It's clear we have to move quickly, a French government source told Reuters on Saturday.

U.N Resolution 1973 calls on Gaddafi to order an immediate ceasefire,  pull back its forces from several rebel-held cities, establish utility services in all the country and allow the entry of humanitarian assistance.

If those conditions are not met, the resolution also allows establishment of a no-fly zone, which involves bombings of Libyan air defenses.

Member states are now authorized to take all necessary measures ... to protect civilians and civilian populated areas under threat of attack in the Libyan Arab Jamhariya, including Benghazi, while excluding an occupation force.