Providing lethal weapons to Ukrainian army is one of the most sensitive issues for Western governments, Russia having warned this would mark a serious escalation of the conflict and pose a threat to its security.
But Ukraine's acting ambassador to NATO, Yehor Bozhok, said there may be no alternative.
"If heavy weapons are withdrawn on our eastern border under the Minsk deal, then fine. But if the situation escalates, then we will again raise the issue of sophisticated defensive weaponry with our western partners," Bozhok told Reuters in an interview.
"We are not going to attack anybody, but we would like to protect ourselves," he said, listing anti-artillery, anti-mortar and anti-tank weapons as those most needed and saying the request "had already been on the table for some time".
Some 8,000 people have been killed in a pro-Russian rebellion launched in eastern Ukraine in April, 2014.
Fighting continued after a peace deal and truce agreed in Minsk in February, until a second ceasefire was sealed on Sept. 1 that seems now to be broadly holding.
The 11-point peace deal requires withdrawal of heavy weaponry and of "all foreign-armed groups" - for Kiev a veiled reference to Russian forces that Ukraine and the West accuse of arming separatists in the eastern Donetsk and Luhansk regions.
"TWO DIFFERENT PLANETS"
Some key conditions of the deal are due to be fulfilled by the end of the year, but the Kremlin has hinted the deadlines could be extended.
Moscow denies providing anything other than political support, although Reuters reported exclusively this month that work had started on a large military base near the Ukrainian border, according to public documents.
Earlier this year, three leading U.S. think-tanks argued that Washington should provide $3 billion in direct military assistance to Ukraine over three years, while U.S. lawmakers also support arming Ukraine's weak army.
Many governments say such a step would only escalate the crisis with Russia over Ukraine, which worsened dramatically in March last year with Moscow's annexation of Crimea.
Russia warned in June that a plan by Washington to station tanks and heavy weapons in NATO states on Russia's border would be the most aggressive U.S. act since the Cold War, and that Moscow would retaliate by building up its own forces.
Bozhok, speaking from his offices at NATO's headquarters in Brussels, said the difference in strength between the Russian and the Ukrainian army was "like two different planets" and that the need for military assistance was clear.
NATO's support for Ukraine, which is not a member of the 28-member military alliance, consists mainly of caring for wounded soldiers, training in cyber defence and helping to rebuild Ukraine's army after years of mismanagement and lack of funding.
Source: Google News