The Turkish and Russian presidents had called for the ceasefire to start on Sunday, more than nine months into an offensive on Tripoli by the eastern-based Libyan National Army (LNA), led by renegade military commander Khalifa Haftar.
Both the LNA and the Tripoli-based, internationally-recognised Government of National Accord (GNA) had said they conditionally agreed to the truce.
However, the GNA said in a statement that it had recorded gunfire in the Salaheddin and Wadi Rabea areas “minutes” after the ceasefire was meant to start at midnight local time on Sunday (22:01 GMT on Saturday).
It said the violations were by “the aggressor’s militias”, but that it “renews its commitment to the ceasefire, and emphasises the need for commitment from the patrons of this ceasefire and the United Nations mission in Libya in applying it optimally”.
“The [GNA] militias violated the truce on more than one battlefront, with all types of weapons,” said LNA commander Al-Mabrouk Al-Ghazawi, adding that forces were waiting for further instruction from LNA general command.
Early on Sunday morning, exchange of fire could be heard in Salaheddin and Ain Zara districts, according to the Reuters News Agency.
Turkey, which recently deployed forces to Libya to support the GNA, said it had observed that all sides were trying to abide by the ceasefire and that the situation was calm except for “one or two separate incidents”.
Al Jazeera’s Mahmoud Abdelwahed, reporting from Tripoli, said any attempt to impose a lasting ceasefire was hard to enforce in the country.
“[This is] especially with the UN-recognised government demanding that Haftar’s forces pull out from southern Tripoli as a prerequisite to any settlement in this conflict,” he said.
The splintered nature of Libya’s military coalitions, with disparate factions and foreign fighters deployed on both sides, makes having a dialogue between the sides difficult. They refer to each other as “militias”.
The ceasefire calls by Turkey and Russia came after the LNA’s advance into Sirte, a strategically important city midway along Libya’s coastline in addition to the offensive on Tripoli.
It also came as the UN and European powers pushed for a summit in Berlin aimed at winding down foreign involvement and resuming a peace process upended by Haftar’s advance.
Anas El Gomati, an analyst working on Libya, told Al Jazeera that the international community needed to find a unified position over the deadly conflict.
He said: “When we think that there is so much disunity in the international community, they have to have a conference about finding a unified position amongst themselves before they can even bring Libyans to the table. That’s the main issue here.”