Serraj made his remarks during a meeting with the European Union Ambassador to Libya Alan Bugeja and German Ambassador to Libya Oliver Owcza, according to a statement issued by the prime minister's information office.
"The prime minister stressed commitment of the Government of National Accord to the national basics in dealing with the situation in Libya locally and internationally, and the necessity of adhering to the Libyan political agreement and its related bodies as a basic reference for any dialogue or agreement, in accordance with the relevant Security Council resolutions," the statement said.
"The prime minister also said that any talk about the cease-fire is linked to withdrawal of aggressor forces (eastern-based army), stressing the need for participation of all countries concerned with Libyan affairs in the upcoming Berlin conference," the statement added.
The eastern-based army has been leading a military campaign since early April in and around the capital Tripoli, attempting to take over the city and overthrow the UN-backed government.
The armed conflict has killed and injured thousands of people, while displacing nearly 120,000 civil.
Germany's Berlin is preparing to host an international conference on Libya, aiming to end the ongoing armed conflict in the country and bring the Libyan parties to dialogue.
( With inputs from IANS )