At least four people died on Tuesday when their vehicle set off an improvised explosive device in a small Kenyan town near the border with Somalia, police said.
The blast was the second in two days to hit border towns after suspected Shabaab militants attacked Mandera, a village some 500 kilometres (310 miles) further north, killing a local chief and abducting two police reservists.
Last October, the Kenyan government decreed a curfew, extended for three months in April, in Mandera county, and also beefed up security in the region to counter such attacks.
Tuesday's attack came in the central eastern town of Liboi, which is some 60 kilometres from Kenya's Dadaab refugee camp, the world's largest and which shelters mainly Somalians.
"Those killed are locals," a senior Liboi police officer said. "They all died on the spot when their vehicle ran over the explosive device."
Another officer said Shabaab militants were suspected.
Police headquarters declined to comment on the incident.
The Islamist Shabaab have spent a decade fighting to overthrow Somalia's internationally backed government, attacking official, military and civilian targets, often using suicide bombers.
Notable encroachments into Kenya included the 2013 Westgate mall and 2015 Garissa University attacks, while the group also attacked the Ugandan capital Kampala in 2010.