At least 12 people were injured on Friday evening after a structure being built near the Humayun's Tomb in Delhi's Nizamuddin area collapsed, officials said.

Police said that a total of 10 to 12 victims were rescued from the debris after a call regarding the incident was received at 3.55 PM. They suffered injuries and were sent to different hospitals, including AIIMS Trauma and LNJP hospitals.

Multiple rescue agencies, including the Delhi Fire Services (DFS), Delhi Police, NDRF and Delhi Disaster Management Authority (DDMA), were pressed into service following the incident.

"The Station House Officer and local staff reached there within five minutes and started the rescue. Some time later, fire personnel and CATS ambulances also reached the spot. NDRF also joined the rescue efforts," a senior police officer said, adding that the rescue operations are still going on.

A senior DFS official had initially said a call regarding the collapse of a portion of a dome at the tomb was received after which five fire tenders were rushed to the spot immediately.

Authorities clarified that the incident did not involve the main dome of the 16th-century monument but a smaller room within its premises.

Humayun's Tomb, a UNESCO World Heritage Site, is a major tourist attraction in the national capital and is visited daily by hundreds of domestic and foreign visitors.

Initial information suggested that eight to nine people were feared trapped under the debris, but subsequent rescue efforts led to at least 11 people being pulled out.

Officials said the area where the collapse occurred was part of the peripheral structure and not the central mausoleum. The cause of the collapse is yet to be ascertained, but preliminary checks suggest possible structural weakening due to recent rains.

"There has been no damage in Humayun Tomb. A new structure was being built near the Humayun tomb, its portion has collapsed, and some of it also fell onto the walls of the Humayun Tomb," Ratish Nanda, conservation architect at Aga Khan Trust for Culture (AKTC), the organisation behind the restoration of Humayun's Tomb, said.

The Humayun's Tomb complex has been the site of a long-standing partnership between the Archaeological Survey of India and the Aga Khan Trust for Culture.

Delhi Traffic Police were asked to keep the route for hospitals clear so that ambulances can reach hospital on time.