In a speech to the Russian parliament, the hardline pro-Russian leader said there were "slightly over a dozen" nuclear weapons left in Belarus from the Soviet era, and if Nato wanted them removed he might "demand guarantees from the West that it will not locate nuclear weapons near Belarus's borders".
Nato intends next year to invite a select group of former Communist countries in central and eastern Europe to join the alliance, and hopes to complete the process by 1999. Among those most likely to join is Poland, which shares a border with Belarus.
Although Nato has no plans to deploy nuclear weapons in Poland, the alliance is wary of striking formal deals with Russia or other non-Nato states that could limit its future freedom of action. Nato hopes to allay Russian concerns by forging a close relationship with Moscow that would be defined in a charter to be negotiated as the enlargement process moves forward.
Mr Lukashenko, who is openly in favour of uniting Belarus with Russia, described his country as "the most stable republic in the post-Soviet system and Russia's most reliable strategic partner". He said that if Nato expanded to the east, Belarus and Russia should "work jointly on an adequate response".
The two countries signed an agreement last April that created a "Russian- Belarussian community", but in practice Russia has held back from taking the decisive steps towards integration that Mr Lukashenko advocates.
He called yesterday for a joint session of the Russian and Belarussian parliaments in January that would decide on the reunification of the two states.
His speech won a sympathetic response from Communist and nationalist members of the State Duma, the lower house of Russia's parliament, who are much keener than President Boris Yeltsin's administration on reuniting Russia with some former Soviet republics.
However, 13 liberal MPs denounced the Communists and nationalists for allowing Mr Lukashenko to address the Duma.
A statement released by the group said: "By supporting President Lukashenko, who is obsessed with establishing an authoritarian regime, the national- Communist majority in the Duma has vividly demonstrated its real position on democracy and human rights."
Mr Lukashenko, criticised in the West for his strong-arm rule, has called a referendum in Belarus to be held on Sunday week to endorse his plans for extra personal powers.
He wants to restart his presidential term from the date of the vote and rule for seven years without re-election. He also wants the right to appoint all senior judges, half the constitutional court, half the commission which organises elections and part of a newly created upper house of parliament.
While warmly embracing Mr Lukashenko, the Russian parliament's majority has angered Ukraine by moving closer to adopting a resolution that would declare Sevastopol, capital of Ukraine's Crimean peninsula, a Russian city and the base of Russia's share of the former Soviet Black Sea fleet.
Georgy Tikhonov, the chairman of the Duma's committee for relations with former Soviet republics, declared that if the resolution on Sevastopol was delayed, "tomorrow it will be Nato's fleet, not Russia's, that will be based in Sevastopol".
Ukraine hit back with a warning that it would seek support from the United States, Britain and France, which guaranteed Ukraine's territorial integrity in 1994 when it agreed to hand over its nuclear weapons to Russia for destruction.
The Black Sea fleet and Sevastopol disputes have prevented Russia and Ukraine from signing a friendship treaty and caused Mr Yeltsin to postpone a state visit to Kiev six times in the last two years.Reuse content