Peace lines are to be lengthened in Belfast as part of new security measures to keep apart rival Protestant and Catholic crowds.
The Northern Ireland Office has also agreed other schemes including a 250 metre extension to a fence close to the city's flashpoint Holy Cross Catholic primary school where violence erupted last month.
It was first erected in 1969, but the new work is to begin immediately.
The total cost of the extensions and modifications is £670,000 sterling and today's announcement by security minister Ms Jane Kennedy followed talks with police chiefs and community representatives.
Several miles of galvanised cladded steel with weld mesh screening, more than 20 feet high, already runs through north and west Belfast, separating the two communities.
There are to be additional security measures in Portadown, Co Armagh, and in Derry close to the Protestant Fountain estate where there have been bitter clashes.
Ms Kennedy said: "It is my hope that these regrettable, but sometimes very necessary structures will provide a significant increase in the level of security in certain interface areas.
"I do not begin this work lightly and have no wish to build barriers between communities. My aim is to see mature dialogue and cooperation. However, as I can attest, physical security is often the only practical solution to the appalling and needless brutality blighting the people of Northern Ireland."
At the height of serious sectarian rioting near the Holy Cross last month the minister was in a police Land Rover which was hit a petrol bomb.
She added: "We have the potential in Northern Ireland to build a society based on mutual respect, justice and equality. But there are those amongst us whose sectarianism threatens to wreck that opportunity."
PA