According to the Guardian the militias have seized control of the central Rixos hotel, which houses the government’s state council.
The plotters issued a statement saying that the coup was an “historic initiative to rescue Libya”. However the presidency asserting that it remained in control has ordered the arrest of the plotters.
Led by Khalifa al-Ghwell, former prime minister , the two sides confronted each other at the Rixos with forces loyal to the Government of National Accord pulling back.
Supporters of the coup appeared to have gained control of the Rixos complex and the whereabouts of the presidency remained unclear.
The political situation has been unstable in Libya, despite the United Nations ordering an orderly handover of power to a unity government headed by Fayez al-Sarraj in March.
It had been hoped the deal, brokered by the United Nations last December, would enable the establishment of a government of national unity.
However last month forces from the elected parliament in Tobruk, which is hostile to the authorities in Tripoli, captured four key oil ports last month.
The regime Colonel Muammar Gaddafi who ruled the country with an iron first for decades was deposed with help of Nato air power in 2011.
A history of UK-Libya relations
1969: Colonel Muammar Gaddafi deposes King Idris in a military coup, paving the way for his “Green Revolution”.
1984: A British WPC is shot dead by pro-Gaddafi gunmen outside the Libyan embassy in London. Britain breaks off diplomatic relations.
1986: Gaddafi denounces Margaret Thatcher as a “murderer and prostitute” for allowing British bases to be used for a US bombing raid on Libya.
1988: A bomb on board Pan Am Flight 103 over the Scottish town of Lockerbie kills 270 people. Libya is suspected.
1999: Gaddafi hands over two Lockerbie suspects for trial before Scottish judges. One of them, Abdelbaset al-Megrahi, is convicted.
2007: Following Gaddafi’s decision to give up its WMD program, Tony Blair meets him in a tent in the Libyan desert, paving the way for oil deals and al-Megrahi’s release.
2011: Britain backs anti-Gaddafi rebels in Libya’s Arab Spring
2016: A scathing report from the foreign affairs select committee is damning about David Cameron’s intervention, saying the decision was made with no proper intelligence analysis and that Britain’s confused involvement contributed to the country becoming a failed start after the fall of Muammar Gaddafi.