KANO, Nigeria: Fears of new violence hung over Muslims at Friday prayers in the Nigerian city of Kano after Islamists who killed at least 185 people there a week ago threatened to strike again.
"People were apprehensive about what might happen in the mosque today," said Musa Danbirni, 58, after attending prayers in the upmarket Nassarawa area of Nigeria's second city.
The purported head of the Islamist sect Boko Haram said in an Internet message that he ordered the gun and bomb attacks that rocked Kano last Friday, the deadliest ever assault attributed to the shadowy group.
"We were responsible," said Shekau in the audio message posted on YouTube. "I ordered it and I will give that order again and again. God gave us victory."
The authenticity of the Hausa language message could not be independently verified but the photo appeared to match others said to be of the Boko Haram leader.
A fresh blast hit Kano on Thursday after gunmen stormed a police post two days earlier, putting resident on edge in the mainly Muslim city, which had previously escaped the worst of Boko Haram's violence.
"Honestly I went to the mosque in fear," said Isa Bello, 58, after leaving prayers in the same mosque. "We ardently hope for unity and understanding between Muslims and Christians in Nigeria."
Boko Haram has previously said that it wants to create an Islamic state in Nigeria's deeply-impoverished mainly Muslim north, and has charged the government with harassing Muslims and raiding Islamic schools.
The group was also blamed for coordinated attacks on Christmas Day, the mostly deadly at a Catholic Church near the capital Abuja where at least 44 people were killed, but the group's victims also include scores of Muslims. Nigeria's Vice President Namadi Sambo on Friday denied that religious tensions were fuelling the Boko Haram menace in the country whose population is roughly divided between a predominantly Muslim north and a mainly Christian south.
"It is very clear that there is no religious problem, religious fighting in northern Nigeria," Sambo told journalists after a meeting with governors from 19 northern Nigerian states.
Elizabeth Donnelly, an Africa analyst at the London-based think-tank Chatham House, said such tensions do exist and that Boko Haram may be using them to boost their strength.
"If they thought it was to their advantage, it would be quite easy for Boko Haram to exploit existing tensions," she told AFP.
There has also been intense speculation about Boko Haram's links to foreign Islamist groups, specifically Al-Qaeda's north African affiliate, known as Al-Qaeda in the Islamic Maghreb (AQIM).
A Western diplomat downplayed the strength of those ties.
"I think there's evidence of contact (with foreign groups), but in terms of operationally linking up with AQIM or extremist groups elsewhere, we don't see Boko Haram as an Al-Qaeda franchise," said the diplomat who requested anonymity.
Shekau was seen as Boko Haram's second-in-command at the time of a 2009 uprising put down by a brutal military assault, after which the group went dormant for about a year before re-emerging in 2010.
In his latest Internet post, he said he does not target civilians, but "enjoys killing those who God commands me to kill the way I enjoy killing chickens and rams."
Gunmen, not immediately linked to Boko Haram, kidnapped a German engineer working with Nigerian construction company Dantata and Sawoe on Thursday, said Kano police spokesman Magaji Majia.
A foreign ministry spokesman in Berlin said Friday "that we have to assume, from the situation, that a German national was abducted in north Nigeria."
A spokesman for German construction firm Bilfinger Berger said the engineer, identified as Edgar Raupach, could be their employee.
The kidnapping of foreigners is rare in northern Nigeria.