Pleas for military help from the Royal Serbian Army and the French Armée d'Orient were rebuffed due to obligations assumed under the Armistice of Belgrade between the Entente Powers and Hungary that defined the Drava River as the line of Hungarian control in the area.

The National Council mounted a new effort on 24 December, sending a 3,000-strong force made up by Slovene volunteers and much of the Royal Croatian Home Guard.

Major Dragutin Perko planned the second incursion into Međimurje in greater detail, and he later commanded a large part of the attacking forces.

Perko was appointed its administrator, and the region was declared a part of the Kingdom of Serbs, Croats and Slovenes with a reference to the principle of self-determination.

The council supplanted the previously established ad hoc group known as the Yugoslav Committee as the body representing the interests of the South Slavs living in Habsburg lands.

[11] The properties of prominent Hungarians were looted, including the Festetics family estate in Gornji Hrašćan and Feštetić Castle in Pribislavec.

[12] By 4 November the revolt had largely lost momentum; the next day, the Zala County prefect authorised summary court-martial proceedings in Međimurje.

In response, National Council defence commissioner Mate Drinković dispatched Major Ivan Tomašević and Lieutenant Viktor Debeljak to Varaždin to devise a plan for the occupation of Međimurje.

Mišić told Perko that Serbia could not intervene due to the armistice but promised support if forces of the State of Slovenes, Croats and Serbs captured Međimurje.

[17] On 13 November, another public assembly was held in Varaždin, at which Tomašević and mayor Pero Magdić announced their plan to launch an attack across the Drava River into Međimurje at 10 p.m. that evening.

The forces commanded by Tomašević fled in disarray to Varaždin across Drava bridges or, after Hungarian cavalry captured both, swam across the river to safety.

The fighting concluded the same day in a truce brokered by Varaždin County prefect Franjo Kulmer and Čakovec District chief justice Pál Huszár.

Because the city boundary of Varaždin extended slightly north of the Drava River, Huszár agreed no Hungarian forces would be posted at the bridges and that security would be enforced by the State of the Slovenes, Croats and Serbs.

[22] According to Simović, Tomašević's defeat was the result of a complete lack of preparation and caused considerable fear of a Hungarian attack against Varaždin.

Three days later, Serbia rejected the request because the Armistice of Belgrade (which had concluded on 13 November) established the Drava River as the boundary of territory under Hungarian control in the area of Međimurje and Varaždin.

A reserve force consisting of one infantry battalion of the Royal Serbian Army was supported by a half of a cavalry squadron and a machine-gun detachment led by Major Aksentije Radojković.

[28] Hungarian forces in Međimurje were considerably smaller; most of them were stationed in Čakovec and small contingents were deployed in large villages in the region.

[29] Kvaternik aimed to first capture Čakovec and the rail and road crossings of the Mura river in Mursko Središće and Kotoriba that connected Međimurje to the rest of Zala County.

By 8 a.m., forces led by Major Karlo Pogledić—assisted by Tomašević (26th Infantry Regiment)—crossed the Drava without opposition, in boats and on rafts procured from local population of Hrženica.

They captured Prelog, followed Donji Kraljevec and Goričan, before advancing to the Mura bridge south of Letenye to block the main road to Budapest.

Perko sent Georgijević to ride into Čakovec and request surrender of the town after capturing sixteen Hungarian soldiers posted to guard its southern approach.

[35] In the afternoon of 24 December, Kvaternik had a letter distributed to clergy in Međimurje, instructing them to read his proclamation urging the population to recognise the new authorities.

Perko was appointed civilian and military administrator of Međimurje; among his first acts in the role were the establishment of Međimurske novine and the banning of Hungarian-language (Muraköz) newspapers.

[36] On 9 January, approximately 10,000 people gathered at the public assembly, which adopted a resolution declaring that Međimurje was seceding from Hungary and acceding to the Kingdom of SHS.

Provisions of the declaration were upheld by the Paris Peace Conference, which defined Hungarian borders through the Treaty of Trianon and left Međimurje to Yugoslavia.