[7] Finland asked for peace conditions again in February, but the Finnish Parliament (Eduskunta) considered the terms received impossible to fulfill.

[18] On June 10, the Soviet 21st Army, spearheaded by 30th Guards Corps, opened the offensive on the Valkeasaari sector, which was defended by 1st Infantry Regiment of Finnish 10th Division.

During the day, the Soviet units captured frontline trenches and destroyed fortifications, shattering the first Finnish defense line at the breakthrough sector.

The Finnish army attempted to buy time by engaging in delaying actions during its retreat so that additional forces from East Karelia would be able to reach the front, and the VKT-line could be prepared for combat.

Though Leningrad Front had managed to capture Vyborg within the time table set by Stavka they had been unable to prevent retreating Finnish units from regrouping and fortifying on the VKT-line.

[17] Unlike many battles on the Eastern Front in the Karelian Isthmus the Red Army was unable to trap any large Finnish units – not even a single battalion.

At the same time more and more Finnish reserves were arriving at the VKT-defense line, where terrain was much more favorable for defenders than for the armored Red Army units.

Late on June 21, German foreign minister von Ribbentrop arrived to Finland in an attempt to extract political concessions from the military help.

Another group would attack northwards to Käkisalmi (now Priozersk, Russia) and surround the Finns defending the eastern VKT-line while preparations would be made for an advance towards Kotka, Kouvola and the Kymi river.

[19][21] It seemed that after Finnish unwillingness to accept the Soviet proposals in April 1944, owing to excessive reparation demands, Finland was to be offered only unconditional surrender.

[23] The Soviet authorities denied this interpretation in an article published in Pravda on July 2, 1944,[24][25] Furthermore, it is also known that at June 26 Stalin even told American ambassador Harriman that US diplomats could try to clarify to the Finns that he did not intend to take over the country.

Less than 40 Finnish tanks and assault guns were modern (StuG III, T-34, KV-1) and less than 60 aircraft too (Bf 109 dayfighter and Ju 88 medium bomber).

[11] The offensive continued on June 25, when the Red Army breached the VKT-line at Tali, between the Vyborg Bay and the Vuoksi river.

When it became evident that a breakthrough was not possible at Ihantala, the Leningrad Front attempted to double envelope the defenders with the twin assaults at the Vyborg Bay and Vuosalmi.

[30] The Soviet troops tried to penetrate deep west after the Battle of Ihantala: in Äyräpää until July 18 and in Karelian Front even in early August.

Although the eagerness of the commanders to evacuate preserved the defending forces, the loss of the islands proved costly because the Soviet Baltic Fleet gained a safe route to Vyborg Bay.

After bringing fresh troops to the front the 21st Army managed to push Finnish lines to Ihantala but failed to create any breakthroughs.

Finnish radio intelligence intercepted many Red Army signals, giving data for effective artillery and air power counterattacks.

The last attempt to resume the offensive was made further north by two divisions of the Soviet 32nd Army which were defeated by counterattacking Finns in the Battle of Ilomantsi.

On June 23, 70th naval infantry brigade attacked and captured a beachhead behind the Finnish lines and also beyond the 'PSS'-line between the Viteleenjoki and Tuuloksenjoki rivers, severing the main road and railroad connections along the shore of Lake Ladoga.

Landing caused some trouble for the defending Finns as it cut the railroad line running along the coast of lake Ladoga.

[31] The Finnish Army retreated further, delaying the Karelian Front's advance, allowing for the U-line, running northwards from Pitkäranta to Loimola and Kivijärvi, to be reinforced.

The first 7th Army units reached the U-line on July 10, but were fatigued following the long offensive and failed to breach the defence line.

7,000-8,000 KIA, MIA, WIA if including losses of last week of July in Ilomantsi area ) and being forced to leave their artillery and other heavy equipment behind.

[32][33] The offensive succeeded in reclaiming East Karelia and driving the Finnish army to the northern side of Viborg Bay and the Vuoksi River.

[36] Despite the losses suffered, the Finnish army managed to avoid encirclement of battalion-size units[Notes 4] and benefited from supplies delivered by Germany.

[38] Based on documents found after 1991 in Russia the most important point of the plan – the destruction of Finnish forces in Karelian Isthmus in a determined time and reaching a certain line (Kotka) – had failed.

In September 1944 the Soviets offered peace terms that were roughly the same as in April 1944, though some of the demands, which had been seen by the Finns as impossible to concede to, were reduced.