Forces loyal to the Libyan government have struggled to retain control of Benghazi, the country's second-largest city. (Mohammed el-Sheikhy/AP)

Two Egyptian officials claimed the country's warplanes had begun bombing positions in Benghazi, the second-largest city in neighboring Libya, on Wednesday, in an attempt to wrest control of the city from the Ansar al-Sharia Islamist militia. The mission, which will be led by Libyan pilots, would mark the highest-profile collaboration between the two North African countries, both of which are beset by instability, since they experienced simultaneous Arab Spring revolutions in 2011. The Egyptian government has officially denied the news.

According to the Associated Press, the mission is slated to last three to six months and will "eventually involve Libyan ground troops recently trained by Egyptian forces."

The Libyan government has struggled to keep the country together in the three and a half years since an uprising overthrew longtime dictator Muammar al-Qaddafi. An oil-rich nation with a population of just 5 million, Libya has not yet formed a government able to rule over the country's vast territory. Islamist militias now control Tripoli, the country's nominal capital, and successfully pushed Libya's "official" government out of Benghazi in June.

The largest of these groups is Ansar al-Sharia. Best known in the U.S. for its role in the 2012 attacks on the American embassy in Benghazi, Ansar al-Sharia has taken responsibility for attacks on both sides of the Libyan/Egyptian border. Ansar forces have fought for Benghazi against General Khalifa Hifter, a one-time opposition figure in Qaddafi-era Libya who has cooperated with Egyptian forces.

"This is a battle for Egypt not Libya," one of the senior officials who leaked the news to the Associated Press said. "Egypt was the first country in the region to warn against terrorism and it is also the first to fight it."

For its part, the American government has stayed out of the Libyan mess—despite repeated requests for assistance—since its airstrikes proved decisive in Qaddafi's 2011 overthrow.

"Libya's problems can really only be solved by the Libyans themselves," John Kerry, the U.S. secretary of state, said in August.