In order to achieve peace in Ukraine, allies must continue to provide "strong support" and avoid a repeat of the Minsk Agreements, NATO Chief Jens Stoltenberg said on July 5.
The first Minsk Agreement was signed in 2014 after the Russian invasion of Crimea, but failed to stop fighting in Donbas between Ukraine and Russian-backed separatists.
Moscow later violated the agreement and the second Minsk Agreements were signed after a successful Russian military offensive in February 2015.
It forced Ukraine to sign a document granting Russian-occupied Donbas wide autonomy in return for Kyiv receiving control over its side of the border with Russia.
"[The Russians] went into eastern Donbas, agreed the ceasefire, Minsk I, violated that, moved the frontline even further west, agreed Minsk II, waited for seven years and then launched the full-scale attack and took even more," Stoltenberg said.
"We cannot have Minsk III."
Speaking ahead of a NATO Summit in Washington next week, Stoltenberg was asked if the alliance would support Ukraine and reject pressure to force Kyiv to accept territorial concessions and non-membership of NATO as a condition for a ceasefire.
"Well, NATO leaders are decisive and strong and that will be strongly expressed at the NATO Summit where I expect a strong package for Ukraine," he said.
"With the new NATO training and assistance for Ukraine, with a NATO command for Ukraine, with a financial pledge, with additional announcements of more military support, with the bilateral security agreements and with everything we do to deepen the cooperation between our military and Ukrainian militaries on interoperability, the new training and education center in Poland and all the other efforts.
"So that will be a strong demonstration of our commitment to Ukraine."
Two top Donald Trump advisors also recently proposed a plan that would cease military aid to Ukraine unless it agrees to cease fire and hold peace negotiations with Russia.
Kyiv has previously rejected similar proposals, saying it would only provide a window of opportunity for Moscow to regroup its forces.