At least 30 people were killed in the far north of Cameroon on Thursday in two successive suicide attacks, military and police sources said.

The first bombing took place shortly before noon in the marketplace of Kerawa, a city on the border with Nigeria, followed by a second attack about 200 meters (yards) from a military camp, said a police officer who asked not to be identified.

General Security chief Maj. Gen. Abbas Ibrahim has said that the cell of Ahmed al-Asir has disintegrated after the arrest of the Salafist cleric at Beirut's airport last month.

In remarks to several local newspapers published on Tuesday, Ibrahim said al-Asir had been put under surveillance since the end of the battles between his supporters and the Lebanese army in Abra near the southern city of Sidon in June 2013.

Suspected Boko Haram gunmen on horseback shot dead nearly 80 people in attacks on three villages in Nigeria's restive northeast at the weekend, a vigilante and residents told AFP on Monday.

The attacks were the latest bloodbath in the six-year-old insurgency by the extremist group aimed at carving out an Islamic state in the volatile region.

Gunmen in Nigeria's southern oil city Port Harcourt have kidnapped a senior journalist working for a private national newspaper, police and the daily announced on Monday. 

Donu Kogbara, a renowned columnist for Vanguard newspaper, was abducted Sunday morning from outside her residence in the southern city, which is capital of Rivers State, the daily said.

Nigeria's secret police said Sunday it had arrested notable Boko Haram suspects, including a key commander, linked with several suicide attacks across the country.

The Department of State Services (DSS) said in a statement that Usman Shuiabu known as Money and other frontline members of the hardline Islamist group were picked up in Lagos, Kano, Plateau, Enugu and Gombe states between July and August.

Chad executed 10 alleged members of Nigeria-based Islamist group, Boko Haram, by firing squad Saturday, a day after they were found guilty of a double suicide killing that left 38 people dead in the capital N'Djamena.

"They were executed this morning on a shooting ground north of N'Djamena," a judicial source told Agence France Presse. The report was confirmed by a security source who asked not to be identified.

Nigeria's domestic intelligence agency has warned travelers to be ready for an attack on the capital's airport after announcing it had smashed a spy network run by the radical Islamist group Boko Haram.

The Department of State Services (DSS) said in a statement late Friday that it had arrested a 14-year-old at Nnamdi Azikiwe International Airport in Abuja who admitted he had been ordered to spy on security procedures.

A court in Chad sentenced 10 suspected members of Boko Haram to death Friday for a double suicide bombing that killed 38 people in the country's capital N'Djamena in June.

"The 10 Boko Haram defendants have been condemned to death," according to the ruling in the country's first trial of presumed members of the Nigeria-based Islamist group.

Relatives of over 200 Nigerian schoolgirls kidnapped by Boko Haram militants marked, on Thursday, 500 days since the abductions with hope dwindling for their rescue despite a renewed push to end the insurgency.

The landmark comes amid a worsening security crisis in northeastern Nigeria, where Islamists have stepped up deadly attacks since the inauguration of President Muhammadu Buhari, killing more than 1,000 people in three months.

Ten suspected Boko Haram members went on trial in Chad on Wednesday over their alleged roles in twin attacks that killed 38 people in the capital N'Djamena in June.

It was the first Chadian trial involving the Nigeria-based Islamist group, which has in the past months stepped up attacks and suicide bombings in Nigeria and the neighboring countries of Cameroon, Chad and Niger.