Diplomatic tensions between Kenya and Tanzania threaten to flare-up over pastures for cattle belonging to the Maasai community who live on the two sides of the border.
On Tuesday, President John Magufuli said his country was not a grazing land for the neighbouring countries' cows.
This followed complaints by Nairobi over Dar's decision to burn 6,400 chicks imported from Kenya for fear of bird flu and auction 1,300 cows belonging to Kenyan herders after they were confiscated for grazing in Tanzania.
Kenya said the "hostile actions" against its citizens and their business interests risked soiling historical relations between the two neighbours.
But Mr Magufuli said his government would continue to confiscate and auction livestock that crosses the border into Tanzania illegally.
"Tanzania is not a feeding farm for animals from other countries and that is why we have stated that we are going to take action as per the law," the president said, adding that "we want to tell our neighbours to take measures based on their laws once our animals graze in their countries".
Further, Mr Magufuli urged Tanzanian herders to brand their livestock in line with a government directive for easy identification and monitoring.
"Most of our land in border regions is being degraded by livestock from our neighbouring countries," President Magufuli said during a visit in the northwestern Kagera region, adding that "This should stop forthwith."
Last month, the Livestock minister Luhaga Mpina launched a 15-day nationwide crackdown of cattle from outside the country's borders. The move, he said was in effort to curb spread of animal diseases and environmental degradation.
So far, Tanzania has seized over 1,300 heads of cattle from Kenya -which were auctioned, and another 6,600 from Uganda.
The auctioned cows belonged to herders in Loitokitok, Kajiado, in southern Kenya. The Kajiado County governor Joseph ole Lenku, an ex-Internal Security minister, accused President Magufuli of "sabotaging good neighbourliness".
He also accused Tanzanian officials of harassing "Kenyans over flimsy grounds".
"I have lobbied for diplomacy to apply when issues arise in mutual respect of East Africa citizens," Mr Lenku said.
A local government official in Loitokitok said cattle from the two countries is usually driven across the borders for pastures whenever there is a drought on either side.
On Wednesday, Kenya's Foreign Affairs minister Amina Mohamed said the government has written a protest letter to Tanzanian authorities.