TOBRUK, Libya — Moammar Gadhafi’s forces struck the rebellion’s heartland with airstrikes, missiles and artillery today, trying for the first time to take back a city that serves as a crucial gateway for the band of fighters who threatened his four-decade hold on power.

The pro-Gadhafi forces surprised rebels with attacks on two sides of the city of Ajdabiya, and the opposition was outgunned.

The assault on Ajdabiya in the east came after Gadhafi forces took back the last rebel town west of Tripoli.

With the victory in Zwara, a seaside town about 30 miles from the Tunisian border, the regime has largely consolidated control in the west, where only weeks earlier his rule seemed to be crumbling. The only other opposition-held city in the western half was under a punishing blockade, its population running out of supplies.

The dramatic turn in Gadhafi’s fortunes has outpaced French and British efforts to build support for a no-fly zone, which fell apart today in the face of German opposition and U.S. reluctance.

Gadhafi said he expects victory, telling the Italian newspaper Il Giornale that the rebels’ options are closing.

“There are only two possibilities: Surrender or run away.”