The Berlin summit was convened after Russian and Turkish-backed ceasefire talks in Moscow ended in failure.
German Chancellor Angela Merkel welcomed the developments and said she also hopes the Berlin conference can reestablish compliance with the UN's weapons embargo on Libya.
During a speech to the Annual Evaluation Meeting for 2019 at the Bestepe National Congress and Culture Centre in Ankara Turkish President Recep Tayyip Erdogan announced that the country will be sending troops to Libya under an agreement with the Government of National Accord.
The Turkish officials were disappointed when Haftar left Moscow without signing the truce agreement, he said, adding Russian Federation is continuing an effort to this end.
European and United States officials said Haftar refused to sign the agreement because an article demanded to be added was rejected, which dictates dissolving pro-Sarraj militias in Tripoli.
Turkey and Russian Federation failed to convince Haftar on Monday to sign a binding truce to halt his nine-month campaign to try to conquer the Libyan capital, Tripoli.
Libya has been torn by violence since longtime ruler Muammar Qaddafi was deposed and killed in 2011.
He explained that the Berlin process on Libya supports the three point-plan Salame has been working to achieve and which ultimately aims to bring Libyan parties to the round table to reach a political solution.
Foreign Minister Heiko Maas extended an official invitation to Libyan Gen. Khalifa Hifter to attend the upcoming conference in Germany, according to a military spokesman for Hifter's forces.
Haftar's offensive against Tripoli upended United Nations efforts to broker a political settlement.
Erdogan warned on Tuesday that Turkey will not refrain from "teaching a lesson" to Haftar's eastern Libyan forces if their attacks against the GNA continue. Haftar and Serraj have also been invited, but it is unclear if they will attend.
Turkey backs Serraj and the Turkish parliament has authorized the government to send troops to Libya.
For Ankara, even if it can not decisively turn the tide in the GNA's favour, it is important for Turkey to create political negotiations and a stalemate that would help preserve its maritime demarcation deal with the Tripoli-based government, which was signed back in November.
Russian Federation and Turkey proposed a cease-fire last week.
Greek premier Kyriakos Mitsotakis has said Athens will veto any agreement brought before the European Union for approval unless a contentious maritime and military deal between Turkey and the GNA is dropped.