New Delhi , India ( CNN ) -- A bomb exploded Saturday at a private hospital in the tourist city of Agra , India , injuring three people . The bomb went off at Jai Hospital 's reception area , said Brij Lal , spokesman for Uttar Pradesh police . The hospital is about 4 kilometers ( 2.5 miles ) from the famed Taj Mahal , India 's most popular tourist destination . The blast blew out window panes and damaged the hospital 's waiting room , where the three injured people were , said P.K . Tiwari , the inspector general of police in Agra . One of them sustain burn injuries . `` It is difficult to say what the cause and motive of the blast were . But we know that this was not a sophisticated device and seems to have not created too much impact , '' Tiwari said . `` My guess is this is a crude bomb . '' Police at the scene said they spotted several unclaimed lunch boxes and bicycles near the blast site . India 's Home Ministry said it had dispatched commandos to Agra and was in the process of collecting evidence from the scene . The Agra blast occurred a day after Indian Prime Minister Manmohan Singh warned the nation 's senior police officers about India 's vulnerability . `` The security environment in the country continues to be uncertain , '' Singh said in remarks at a police conference Friday . `` The recent terrorist attacks in Mumbai and Delhi are grim reminders of the grave challenges posed by terrorism to our national security . '' India has suffered a spate of attacks in recent years , including the November 2008 siege of Mumbai that killed 163 people . This month , a bomb inside a briefcase at the high court in the capital , New Delhi , killed 11 people and injured 74 others . The Islamic extremist group Harkat-ul-Jihad-al-Islami claimed responsibility for that attack in an e-mail to several TV news channels . Authorities have detained three suspects from the Kashmir region . In July , 19 people were killed in three deadly blasts in Mumbai , India 's largest city and financial hub . No one has been arrested yet . CNN 's Aliza Kassim contributed to this report .
NEW : Police say it was a crude device . NEW : The three injured were in the hospital 's reception area . Agra is home to the famed Taj Mahal , India 's most popular tourist spot . No motive has been determined yet .