The prayer is established while one is performing tawaf
Machine translationRead the Arabic original
Question:
Honorable Shaykh, may Allah grant you success. He says: If a pilgrim or one performing 'Umrah has completed some of his tawaf, and then the call to prayer is made, does he continue from where he left off?
Answer:
No. The lap in which he prayed must be repeated from the beginning, but the laps before that are valid, and he builds upon them. Yes.
Honorable Shaykh, may Allah grant you success. He says: If a pilgrim or one performing 'Umrah has completed some of his tawaf, and then the call to prayer is made, does he continue from where he left off?
Answer:
No. The lap in which he prayed must be repeated from the beginning, but the laps before that are valid, and he builds upon them. Yes.
Source
شرح كتاب المنتقى من أخبار المصطفى صلى الله عليه وسلم، بداية من أبواب الأذان — islamhouse.com (1:08:21)
The Arabic text is a machine transcription of the audio recording.