The incident took place late last night, police said.
After sexually assaulting her, the four accused abandoned the woman at a secluded place and fled, they said.
Based on her complaint, a case of rape has been registered.
The woman, who lives in Nand Nagri area of Delhi, told in her complaint that she had come alone to offer prayers at a 'dargah' (shrine) in Artala area yesterday.
She alleged that her landlord's son Hemant and Lala, along with two others were following her.
They also threatened her not to reveal the matter to anyone.
Her medical examination has been conducted and the report is awaited, the officer said, adding that a manhunt is on to arrest the four accused.
