"If Sweden, and Finland don't fulfill the necessary conditions, Türkiye will freeze their NATO accession process, Turkish President Erdoğan said on Monday.
"NATO's expansion policies should go in line with the sensitivities of our country," he added.
Referring to conditions in a memorandum the two Nordic countries signed with Türkiye at last month's NATO summit in Madrid, Recep Tayyip Erdoğan warned after a Cabinet meeting in the capital Ankara: "I repeat it again that we will freeze their NATO accession process if the conditions are not met."
Earlier this month representatives from NATO's 30 member states signed accession protocols for Finland and Sweden after formally inviting them to join the military alliance.
Spurred by Russia's war on Ukraine, the two countries applied to join NATO in May, shedding their traditional neutrality.
But Türkiye voiced objections to their membership bids, criticizing the countries for tolerating and even supporting terrorist groups such as the YPG/PKK and the Fetullah Terrorist Organization (FETO), the group behind a defeated coup in Türkiye in 2016.
Ahead of the summit, Ankara and the two Scandinavian countries signed the memorandum after four-way talks, including NATO.
The agreement allows the countries to become NATO members but requires them to take steps on Türkiye's terrorism concerns and lift an arms embargo on Ankara.
Following the trilateral deal, NATO formally invited Sweden and Finland to join the 30-member military alliance.
Erdoğan also remembered the defeated coup in Türkiye on July 15, 2016, which the country marked the sixth anniversary last week.
"It is our duty to ensure that the July 15 betrayal, which was foiled by our nation with a foresight, courage and self-sacrifice that is rare in the world history, is remembered for generations."
Türkiye on Friday commemorated those killed during the defeated coup.
Since its designation in October 2016, every year, the country marks July 15 as Democracy and National Unity Day, with events held to commemorate those who lost their lives beating back the putschists and remembering the bravery of the nation.
FETO and its US-based leader Fetullah Gulen orchestrated the defeated coup, which left 251 people dead and 2,734 injured.
Ankara also accuses FETO of being behind a long-running campaign to overthrow the state through the infiltration of Turkish institutions, particularly the military, police and judiciary.
