Release International has called on the new Nigerian president to ensure greater protection for vulnerable Christians in the country after seven were killed earlier in the month.

Partners of Release say that armed men in military uniform shot dead seven Christians in Kizachi Dawai Chawai, Kaduna state, on July 3.

The gunmen surrounded the village at about 8.30pm and began shooting indiscriminately. The dead included a primary school teacher and a mother of six. Five others were taken to hospital with gunshot wounds.

The following day, assailants wielding guns and machetes attacked Ganawuri, a village near Jos, in neighbouring Plateau state. The Jos area was the scene of brutal violence against Christians in March which left 520 people dead, including many women and children.

Release sources say that the gunmen in both these latest raids were suspected Fulani militants from Kaduna.

These same sources now accuse the Nigerian military of not doing enough to protect vulnerable Christian communities. One source reports that police had withdrawn from Kizachi Dawai Chawai the day before the attack, because the government had allegedly failed to pay their salaries.

Release said: "We're appalled to hear of yet more violence against Christians, who have been warning for some time now that they feared further attacks.

"We appeal to President Goodluck Jonathan and his administration to take firm action now to ensure that the military and police carry out their full responsibilities and protect Christians properly. We acknowledge it is a huge task – but enough is enough."

President Jonathan, who is from the mainly Christian south of Nigeria, was officially sworn into office in May, after the death of the previous incumbent, Umaru Yar'Adua.

Plateau is located in the centre of the country between the largely Muslim north and the south. Along with religious tensions, tribal and political differences have seen an increasing polarisation between different ethnic groups there.

Kaduna, just north of Plateau, has also been a flashpoint for conflict between Christians and Muslims, most notably during the 'Miss World riots' in 2002 when a newspaper's alleged blasphemy against Islam's prophet Mohammed sparked widespread violence against Christians.

Release urged Christians in the UK and Ireland to stand with the church in central and northern Nigeria.

"Christians in Plateau and Kaduna are standing firm despite intolerable persecution – but they desperately need our prayers," it said.

"And let's pray too for strength and wisdom for those in authority, including President Jonathan, so they can find a lasting solution to end this cycle of violence."