NAIROBI: A diplomatic spat over cows and chickens has worsened already frosty ties between Kenya and Tanzania, with Nairobi lodging a formal protest against its neighbour, the foreign minister said Wednesday.

The latest impasse between the two east African nations began last month when Tanzania seized and auctioned off 1,300 cattle which had wandered across the border to graze in a region where herders typically pay little heed to frontiers.

Then, last week, Tanzania seized and burnt alive 6,500 chicks that had been brought into the country by a trader, fearing they would spread disease.

Kenyan Foreign Minister Amina Mohamed said the country´s representative at the East African Community (EAC) bloc had sent a "note of protest" to Tanzania.

A series of diplomatic and trade squabbles have soured relations between the neighbours in recent months.

Kenyan traders have complained of mistreatment by Tanzanian immigration agents, which has sparked protests at the border, and tit-for-tat trade jabs have seen the two nations blocking the import of various goods from either country.

In March last year, Kenya´s energy minister and his delegation were blocked from entering Tanzania, while their Ugandan counterparts were allowed in unhindered.

This was ahead of a meeting on whether Uganda would pass a proposed oil pipeline through Tanzania or Kenya.

Kenya eventually lost the lucrative deal to Tanzania.

Tanzania´s President John Magufuli, increasingly criticised over his iron-fisted rule, warned Kenya that any livestock wandering into his country would be confiscated.

"Those who sneak with their livestock into this country will not be spared," he said in comments carried in local media.

Mohamed said the herders had "not committed any crime because they had done what they always did, which is cross the border to look for pasture, and that is the normal behaviour that we all have," referring to grazing practices around the region.

"These are people who have lived together forever, they have intermarried, they move from side to side. We should make it easier to cross the borders of our countries."