Given the task definition and input, reply with output. This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Passage: By July 1944, the Red Army was deep into Polish territory and pursuing the Germans toward Warsaw. Knowing that Stalin was hostile to the idea of an independent Poland, the Polish government-in-exile in London gave orders to the underground Home Army (AK) to try to seize control of Warsaw from the Germans before the Red Army arrived. Thus, on 1 August 1944, as the Red Army was nearing the city, the Warsaw Uprising began. The armed struggle, planned to last 48 hours, was partially successful, however it went on for 63 days. Eventually the Home Army fighters and civilians assisting them were forced to capitulate. They were transported to PoW camps in Germany, while the entire civilian population was expelled. Polish civilian deaths are estimated at between 150,000 and 200,000.
What army was pushing deep into Polish territory to pursue The Home Army fighters in 1944?