Russian soldiers found themselves under crossfire from all sides and from buildings, and several units broke early and suffered heavy casualties in their retreat.

[9][8] Upon receiving news of Kościuszko's proclamation in Kraków (24 March) and his subsequent victory at Racławice (4 April), tension in Warsaw grew rapidly.

[10] Polish king Stanisław August Poniatowski was opposed to Kościuszko's uprising, and with the Permanent Council issued a declaration condemning it on 2 April.

[16][20] At the same time bishop Józef Kossakowski, known for his pro-Russian stance, suggested that the churches be surrounded on Holy Saturday on 19 April with troops and all suspects attending the mass be arrested.

[36] The regiment was stationed in its barracks in Żoliborz, away from the city centre, but it was also responsible for guarding the Royal Castle and some of the strategically important buildings.

[41][42] Kazimierz Bartoszewicz in his monograph of the Uprising assesses that the number of townspeople serving in various irregular militia forces did not exceed 3000, and probably totalled between 1500 and 2000.

[34] The Russian garrison of Warsaw had a nominal strength of 11,750 men, including 1500 cavalrymen, at least 1000 artillerymen with 39 guns and an unspecified number of Cossacks.

[43] In addition, Igelström could request assistance from a Prussian unit of General Friedrich von Wölcky stationed west of the city in the fields between Powązki and Marymont.

[46] On Holy Wednesday the Polish garrison was secretly provided with volleys and artillery charges and overnight was dispatched to various parts of the city.

[48] Soon afterwards the remainder of the Royal Horse Guard regiment left the barracks on foot and headed in two directions: towards the outer gates of the city at Wola and towards the Warsaw Arsenal, where the Russian forces were preparing an assault.

[16] The crew of the Arsenal was also joined by a small troop of National Cavalry under Colonel Jan Jerzy Giessler, who crossed the Vistula overnight.

The small troop pledged to defend the monarch as soon as he appeared at the Castle's courtyard, but on hearing the sounds of a battle nearby, the unit left the king and joined the fighting at Miodowa Street;[51][52] The Russian forces, pushed back after their initial failure at the gates of the Arsenal, withdrew towards Miodowa Street, where they amassed in front of Igelström's palace.

[53] By 07:00 the confusion was partially cleared and heavy fighting at Miodowa street turned into a regular battle in the vicinity of both the Arsenal and Igelström's headquarters, as both sides struggled to secure both buildings.

[16] At 06:00 the Polish 10th Regiment of Foot under Colonel Filip Hauman had left its barracks at Ujazdów to the south of the city centre, and started its march towards the Royal Castle.

[55] It was stopped by a Russian force at Krakowskie Przedmieście Street, consisting of no less than 600 men and 5 pieces of artillery, and commanded by General Miłaszewicz.

[55][56] The Russian force was strategically dislocated on both sides of the street, in both the Kazimierz Palace (now the Warsaw University rectorate) and before Holy Cross Church.

[20][62] After noon the fighting in front of Igelström's headquarters, at Miodowa Street and for the Arsenal continued as both sides drew reinforcements from all parts of the city.

[63] Russian units put up the strongest defence and although they were forced to retreat in the direction of the Franciscan church, they repelled early Polish attacks and captured the Krasiński Palace which the Poles had been using to fire on them from behind.

[16] Nearby, a Russian force under Major Mayer, consisting of two companies, each armed with a cannon, fortified itself in the Kwieciński's Baths, where it defended itself for several hours.

[63] There it was met by a negligible unit of not more than 100 civilians armed with a single 6-pounder cannon,[note 3] commanded by Captain of Artillery Jacek Drozdowski.

[61][69] When a company of the 10th Regiment returning from Powiśle appeared at Królewska Street, the Russians started a disorganised retreat towards Jerusalem Avenue, leaving Igelström to his fate.

[74] The Poles secured the courtyard and placed a cannon there, which allowed them to storm the monastery, but fierce hand-to-hand fighting, with heavy losses on both sides, continued until late evening.

[61][74] In the early morning of 18 April, Mokronowski concentrated on the main remaining Russian stronghold in the city — the embassy at Miodowa Street.

[75] He planned to prepare a sortie in order to break through from the city centre, but all surrounding streets were filled with Polish troops and cannons.

[76] The remaining troops defending the embassy and covering Igelström's retreat eventually ran out of ammunition and their positions were overrun by 17:00 by the forces of the 10th Regiment under Kalinowski, aided by Kiliński's militia.

The king refused and power in the city was seized by the Provisional Temporary Council (Polish: Rada Zastępcza Tymczasowa) composed of Zakrzewski, Mokronowski, Józef Wybicki and Kiliński.

[83] A few weeks later, on 28 June, an angry mob stormed the prisons and hanged other supporters of Targowica, including bishop Ignacy Jakub Massalski, prince Antoni Stanisław Czetwertyński-Światopełk, ambassador Karol Boscamp-Lasopolski and others.

[85] Kosciuszko quickly put an end to the lynch mob declaring, "What happened in Warsaw yesterday filled my heart with bitterness and sorrow ...Those who do not obey the laws are not worthy of liberty.

"[86] The National Militia of Warsaw grew to over 20,000 men at arms and constituted a large part of the Polish Army fighting against Russia.

The defeat in this battle is sometimes seen as one of the reasons for the massacre of Praga, in which the Russian forces killed between 10,000 and 20,000 civilians[note 7] of Warsaw upon their reconquest of the city later that year.