The Egyptian military is reinforcing the Egyptian-Libyan with its own guards, after Libyan border guards withdrew from the Egyptian-Libyan border, as reported on the Libyan army's Facebook page. Egyptian reinforcement is intended to both protect violent spillover into Egypt, as well as to ensure that the border remains open, now 24 hours a day, to allow the sick and injured to enter. The Salum passage, the main crossing on the coast between Egypt and Libya, had previously been open only for a few hours a day. A military source said the military council had decided to "reinforce the borders with border guards to secure the Egyptian border with Libya and will open the Salum passage throughout the day for medical conditions and those stuck."
In 1977, a short border war ensued between Libya and Egypt. After the Yom Kippur War of 1973, Qaddafi fiercely opposed Sadat's peace policy with Israel, and the two countries split on their relationship with Moscow. Furthermore, in 1975, Egypt gave assistance to the attempted Qaddafi coup staged by the Revolutionary Command Council, whose motto was "freedom, socialism and unity", and which sought an active role in the "Palestinian cause". In 1976, Egypt claimed to have discovered a Libyan plot to overthrow the Egyptian regime. Later that year, a bomb exploded in a Tahrir Square government office, which Egyptian government officials and media blamed on Libyan agents. Throughout 1976, Egypt concentrated troops on the Libyan border, backed by the US. International assessements predicted Sadat would attack Libya in an attempt to overthrow Qaddafi.
In 1977, demonstrators in each country attacked each others' embassies. In June 1977, Qaddafi ordered the 200,000+ Egyptians in Libya to leave in one month's time. The direct war occurred for several days along the Egyptian-Libyan border. Read more about the war here. After the war, Arab governments sided with Egypt, while pro-Soviet and leftist states sided with Qaddafi. In the New York Times, a Palestinian wrote after the Egyptian-Libyan war: ""If the Arabs haven't got Israel to fight, they will be fighting each other." Is that what is happening today?
This is bound to get interesting - Egyptian leadership, against which the people rebelled, has always been anti-Qaddafi. Yet the Egyptian people are likely to feel a solidarity with the Libyan people. This means everyone in Egypt is eager to see Qaddafi gone. The open border is already somewhat of a statement in favor of the protests. Will Egypt get further involved?