Three men were arrested following the explosion and are being suspected to have been in a black SUV.
A special commission has been set up to probe an explosion at a gurudwara in Germany as authorities in the western city of Essen assured India that all steps will be taken to ensure security for all minorities including the Sikhs.
Indian Consul General in Frankfurt Raveesh Kumar, who rushed to the Nanaksar Satsang Darbar Gurdwara following the attack, was apprised of the current level of investigation and the situation during meetings with Essen's Mayor Thomas Kufen and Police Commissioner Frank Richter yesterday.
"We (police department) have set up a commission of inquiry and are thoroughly probing. The security for religious institutions will be beefed up," Mr Richter told Mr Kumar, who visited the Sikh community to show solidarity besides holding talks with authorities.
The explosion ripped through the entrance hall of the gurdwara on Saturday evening during a wedding ceremony and severely damaged part of the building housing the gurudwara besides shattering several windowpanes and injuring three persons, including the Sikh priest or 'granthi'.
India had expressed "distress" at what is being deemed as a deliberate act.
Police in Essen said in a statement that they are focussing their investigation on the possibility that the explosive device was planted inside the foyer of the gurudwara or lobbed into it from outside.
They are searching for a masked man dressed in black, who was seen by eyewitnesses fleeing the area soon after the detonation.
Police said so far they have no indication that the attack on the gurudwara was racially motivated or whether it has any terrorist background.
Three occupants of a car parked near the gurudwara, who were taken into custody on suspicion of involvement in the explosion, were set free after questioning on Saturday night.
The mayor assured Mr Kumar that the city administration, the police and the state prosecutor's office would take all necessary measures to ensure that the Sikh community can feel secure, the city of Essen and the police commissioner's office said in a joint statement.
Religious freedom is guaranteed in the German society and any form of violence against religious minorities will be totally unacceptable, Mr Kufen said.
Mr Richter said police so far have no indications of a terrorist background, "but we are investigating in all directions and thereby we are working closely with the Indian authorities".
Mr Kumar and Mr Kufen jointly visited the Sikh community after their discussions and the mayor conveyed his solidarity and the city's support to protect them, the statement said.
Ambassador of India to Germany Gurjit Singh tweeted: "Mayor and police chief of Essen promise full investigation into Gurdwara incident. Mayor joined CG Frankfurt to address sangat (prayer meeting) at Gurdwara."
The Ambassador also said that the 60-year-old 'granthi' Kuldeep Singh, who suffered deep cuts after the whole pane of glass fell on him due to the impact, was recovering and in "good spirits".
The other two 47- and 56-year-old men who suffered minor injuries have been discharged from the Essen hospital, which the Consul General also visited.
Eyewitnesses have spoken of "a kind of bomb" that exploded at the gurudwara where about 200 people, including many children, were present at a wedding ceremony that began very late and was ongoing when the explosion occurred.
The gurudwara, one of the main places of worship for the Sikh community in the German state of North Rhine Westphalia, as well as the residence of the Sikh community's president have been put under police protection.