The U.S. military has reportedly doubled the number of planes on standby in Italy, to assist in the event of an evacuation of Americans from the U.S. embassy in the troubled Libyan city of Tripoli.

Four additional U.S. V-22 Osprey planes "arrived overnight" at Italy’s Sigonella naval base, joining four other planes and 200 Marines who reached the naval base last week, CNN reported, citing a defense official. The additional aircraft will help the evacuation of more than 200 people from the embassy. The decision follows Sunday’s incident where gunmen entered Libya’s interim parliament in Tripoli, killing two people and wounding more than 50, while gunshots and explosions continued on the outskirts of the capital until Monday. 

"The government condemns the expression of political opinion through the use of armed force," Salah al-Marghani, the justice minister, said, according to the Guardian, adding: "It calls for an immediate end of the use of the military arsenal … and calls on all sides to resort to dialogue and reconciliation."

Nuri Abu Sahmain, speaker of the interim parliament who is backed by Islamist forces, reportedly decided to deploy the Central Libya Shield Forces, or CLSF, in Tripoli. The CLSF is one of the strongest Islamist-affiliated militias and their entry into the capital to fight the gunmen, who are believed to be supporters of former Libyan dictator Moammar Gadhafi, is feared to intensify violence in the region.

Meanwhile, the U.S. expressed concern over the deterioration of the political situation in the country and said that even though a decision has not yet been made to immediately move its citizens out of Libya, such a move has not been ruled out. 

“We remain very concerned about the violence over the weekend in Tripoli and Benghazi. We reiterate our call for all parties to refrain from violence and to seek resolution through peaceful means,” Jen Psaki, spokesperson for the U.S. Department of State said, in a briefing Monday, adding: “The situation on the ground, obviously, could change quickly, and so we’ll continue to evaluate and update our posture as needed.”

The aircraft and marines belong to the Marine Air-Ground Task Force Crisis Response team, which was formed after the attack on a U.S. diplomatic compound in the city of Benghazi in 2012, which killed Ambassador Chris Stevens and another embassy official.