* Health workers administering polio vaccines
* Islamists Boko Haram behind recent attacks (Adds details, background)
ABUJA, Feb 8 (Reuters) - Gunmen shot dead two health workers who were administering polio vaccinations in Nigeria's main northern city of Kano on Friday, police said, in the latest in a string of violent attacks.
Islamist militant group Boko Haram - a sect which has condemned the use of Western medicine - has been blamed for carrying out a spate of assaults on security forces in the city in recent weeks.
"Two are dead and one sustained injuries after being shot by unknown gunmen ... They were working for the state government giving out polio vaccinations at the time of the attack," said police spokesman Magaji Musa.
Boko Haram wants to impose Islamic law, or sharia, on a country of 160 million split roughly equally between Christians and Muslims.
The movement is seen as the most serious threat to the stability of Africa's top energy producer.
Friday's attack will be a further setback to efforts by global health organisations to eradicate polio in Nigeria, one of only three countries, along with Pakistan and Afghanistan, where the disease remains endemic. (Reporting by Joe Brock; Editing by Andrew Heavens)