Unidentified gunmen shot dead at least three people near the Kenyan port city of Mombasa and distributed leaflets claiming revenge for an attack that killed at least 60 people at the coast.

Twelve people were injured in the shooting at Likoni, about 6 kilometers (3.5 miles) south of Mombasa’s city center, the Kenya Red Cross said in a statement on its Twitter account. Police arrested eight suspects in connection with the attack, Mombasa Police Commander Robert Kitur told reporters today.

“We are narrowing down on them,” he said. “We will stop these criminal gangs.”

The al-Qaida-linked militant group, al-Shabaab, has claimed responsibility for several attacks at Kenya’s coast since mid- June, including one at Mpeketoni in Lamu county in mid-June that left at least 60 people dead. Kenyan President Uhuru Kenyatta’s government says the violence was motivated by political and land grievances.

Mpeketoni was settled about four decades by ethnic Kikuyu under a program carried out by Jomo Kenyatta, the father of Kenya’s current president. The leaflets distributed during yesterday’s attack said the shootings were “revenge for our brothers who were killed in Mpeketoni.”

Mombasa hosts East Africa’s biggest port, which serves countries including Uganda, Rwanda, South Sudan and the Democratic Republic of Congo.

On July 18, at least seven people, including two security personnel, died when gunmen attacked a bus near Lamu. Al-Shabaab said it was responsible for the assault.

Kenya Police Inspector-General David Kimaiyo yesterday ordered a dusk-to-dawn curfew in Lamu county.

Al-Shabaab has threatened to attack Kenya in retaliation for the country’s deployment of troops in Somalia, where the militia is trying to overthrow the government and establish Shariah, or Islamic law. Kenyatta has vowed to keep the troops in place until the threat of al-Shabaab is thwarted.

Tourism, Kenya’s biggest foreign-currency earner after tea, has been dented by attacks in the country, with arrivals of holidaymakers falling 18 percent to 1.4 million last year.