Kremlin officials demanded that the Act be annulled, interpreting it as a secessionist affair, but Lithuania ignored them, arguing that they were coerced to join USSR back in 1940.

The economic blockade restricted or cancelled the centralised supply of energy resources, on which Lithuania was extremely dependent from USSR, as well as electricity, foodstuffs, and pharmaceuticals.

As the rebel republic felt crippling shortages of essential items, Western countries pressured Lithuania and the Soviet Union to reach a compromise, which initially could not be achieved.

Enterprises created partnerships with fellow companies and Lithuania negotiated trade agreements with other republics, marking a transition to capitalist economics.

By late summer 1988, Sąjūdis, the movement which was initially in favour of perestroika, started to demand legalisation of the Lithuanian interwar flag, resignation of the republic's government and sovereignty for Lithuania.

At the same time, revelations in Lithuania concerning the secret protocols of the Molotov-Ribbentrop pact (whose existence the USSR had denied) further angered the opposition, which demanded their disclosure and condemnation.

[16] The Soviet Union formally acknowledged their existence in December 1989, following deliberations of a select committee in the Congress of People's Deputies, and declared them "legally untenable and invalid from the moment they were signed".

[31][a] Landsbergis government promptly responded with a letter which asserted that the resolution of the Congress of People's Deputies was illegal and insisted on talks on equal footing between the USSR and Lithuania.

[33] In late March, the Soviet government ordered to reinforce troops in Lithuania, introduced about 100 tanks and 1,500 soldiers to the streets of Vilnius and captured some strategic buildings, including the prosecutor's office, the Vilnius airport, the Party Historical Institute, the headquarters of the Communist Party of Lithuania, and printing offices of the main newspapers and journals of the republic.

Therefore, Gorbachev decided to try an economic blockade instead, hoping to instigate a popular revolt against the Lithuanian leadership and to force it to rescind the independence declaration.

[22][27][40] This solution, formalised in an order of the USSR Council of Ministers on 17 April,[42] was chosen despite the fact that the previous month, Yuri Maslyukov, the director of Gosplan, the Soviet central planning committee, was assuring that an embargo would not happen as he thought it would be detrimental to both sides of the conflict.

The blockade worsened a few days later, when the USSR stopped supplying coal, electricity, paper, foodstuffs and pharmaceuticals, including the most essential drugs and vaccines for hospitals.

[26][51] According to M. Gaškienė, who was responsible for coordination of food supply chains within Lithuania, the only factories which were not impacted by the effects of embargo were the ones that still were under direct control of the Soviet Union.

[37] In particular, some of the exports that were primarily produced in Lithuania (such as vacuum cleaner parts, pneumatic brakes, TV tubes and black boxes) could not be brought back to the Soviet Union.

On 20 April, François Mitterrand, President of France, and Helmut Kohl, Chancellor of Germany, urged Lithuania to temporarily suspend the independence restoration process and asked to negotiate with Moscow.

Western leaders generally feared destabilisation of the situation in the Soviet Union and wanted Gorbachev in office, as the West perceived him as a friendly ruler and a guarantor for democratic transition in Eastern Europe.

[61] The Landsbergis government initially insisted that the independence restoration act could not be subject to negotiations, while the Soviet side demanded that it be annulled before any discussion could occur.

[32] However, on German and French advice, when Prunskienė met with Gorbachev on 17 May, she announced that the independence restoration process could be suspended, which TASS, the Soviet state news agency, suggested was the minimum requirement for the negotiations to start.

Moreover, regular visits of the Lithuania's Prime Minister gradually led the Lithuanian leadership to believe that temporary suspension of the restoration act was inevitable to reduce tensions.

On 30 May, the Leningrad city council urged the central government to begin negotiations with the republic under blockade,[46] and Moldavian SSR voted to recognise the independence of Lithuania the following day.

[67] On 16 June, the Soviets increased the flow of gas from 15% to 30% of the level before the blockade and let some deliveries of raw materials in, which enabled partial reopening of some industrial plants, including Jonava's fertilizer facility.

[38] Oil deliveries were resumed by the evening of 30 June,[73] while on 2 July, the blockade was fully lifted,[37] which Nikolai Ryzhkov, Chairman of USSR's Council of Ministers, confirmed the following day.

[21] Lithuania's economy was tightly integrated in the USSR's and, while relatively developed, was still subordinated to the needs of the Soviet Union and was using little local input as a result.

[80] For example, Juozas Olekas, then-Health Minister of Lithuania, noted that the country lacked medical supplies, but managed to establish a good relationship with Denmark, thanks to which the shortage of vaccines for hospitals was largely alleviated.

[50] The government of Lithuania and local industries started to actively search for direct relations with the enterprises (which were not subject to embargo),[80] often engaging in barter trade with oil-rich republics (e.g. oil for butter or meat), such as the RSFSR and the Kazakh SSR.

[81] The blockade's effects were also somewhat mitigated by smugglers operating on Lithuania's borders, as well as by the regiments of the Soviet Army stationing in the country, which were clandestinely selling the reserves of oil products they had in the garrisons.

[15][82] At the same time as the relations with the Soviet Union deteriorated, the conflict was brewing between the Lithuanian majority and the Polish minority in the south-eastern part of Lithuania and the Russians in Sniečkus, where the Ignalina Nuclear Power Plant was located.

[90] While the first attempts to introduce Polish self-government (or autonomy) started in late 1988 and early 1989, the movement gained significant momentum after the Act of 11 March, and its escalation happened during the blockade.

However, on 1 June, delegates from majority-Polish regions appealed to the Lithuanian government, not the Soviet Union, to create a self-governing entity, which they argued was the only way to ensure that the rights of Poles are respected.

Van Horne and Alfred Erich Senn suggest that Moscow helped the Polish regions weather the blockade[97][98] (though M. Gaškienė, a senior government official, wrote to Algimantas Gureckas that the blockade was applied uniformly across Lithuania),[25] while Anatol Lieven underlines that the Association of Poles in Lithuania actually supported independence, but faced stiff competition from Polish anti-independence candidates.