Police in Kenya has said they had thwarted a terror attack in  Garissa County after unearthing a large cache of weapons and ammunition, adding that they are now on heightened alert.

The cache – including grenades, 210 rounds of ammunition, improvised explosive devices, guns, and a suicide vest – is believed to belong to al-Shabaab militants who might have snuck into the country through the porous Kenya-Somali border.

In a statement, Kenya police spokesman George Kinoti said that police is aware that al-Shabaab militants are amassing forces in the Jedahaley area in Somalia in an attempt to infiltrate the country.

“In an effort to outwit our security agencies, al-Shabaab militants are now making attempts to change tactics by splitting into smaller groups and infiltrating the country especially along the border areas of Mandera, Wajir, Garissa, and Lamu counties,” Kinoti said.

He added that security forces believe possible targets include security establishments along the border and public vehicles used by area residents.

“We have since heightened security alertness to avert attacks,” he said.

This discovery came just hours after police in Kenya’s Mandera County ran over an improvised explosive device planted on the roadside but escaped unhurt.

In previous years, the Somali-based Al-Qaeda-affiliated militant group has carried out numerous attacks on Kenyan soil in the days leading up to the Christmas holidays.