Nancy Pelosi's older brother has died at the age of 90 following complications from a stroke, it has been announced.

Thomas D'Alesandro III died at his North Baltimore home Sunday. His sister called him 'the finest public servant I have ever known', in a statement.

Pelosi said his 'life and leadership were a tribute to the Catholic values with which we were raised: faith, family, patriotism'.

In a statement the House Speaker added: 'My husband Paul and our entire family are devastated by the loss of our patriarch, my beloved brother, Thomas D'Alesandro III.'

Thomas D’Alesandro III, pictured here in 2016, a former Baltimore mayor and the brother of House Speaker Nancy Pelosi, has died at the age of 90

Speaker of the House Nancy Pelosi, D-Calif., center, laughs as her brother Thomas D' Alesandro III, right, makes a joke as he introduces her husband Paul, left, during a street renaming ceremony in her behalf in 2007. D'Alesandro died at his home on Sunday

The University of Maryland Law School graduate was mayor of Baltimore from 1967 to 1971, vowing to 'root out every cause or vestige of discrimination'.

Alesandro was mayor of the city during the 1968 riots. His and Pelosi's father, prominent Maryland politician Thomas D’Alesandro Jr., also served as mayor in the city for 12 years.

D’Alesandro served as Baltimore City Council president and then as mayor. The elder D’Alesandro also served as a state delegate and congressman.

The younger D’Alesandro didn’t seek re-election as mayor and went into private law practice.

He is now 'with the angels', Pelosi said Sunday. Alesandro is survived by his wife Margaret, children Thomas, Dominic, Nicholas, Patricia and Gregory, and ten grandchildren.

Pelosi added: 'Tommy was the finest public servant I have ever known. His life and leadership were a tribute to the Catholic values with which we were raised: faith, family, patriotism. He profoundly believed, as did our parents, that public service was a noble calling and that we all had a responsibility to help others.

'Tommy dedicated his life to our city. A champion of civil rights, he worked tirelessly for all who called Baltimore home. Tommy was a leader of dignity, compassion and extraordinary courage, whose presence radiated hope upon our city during times of struggle and conflict.

'All his life, Tommy worked on the side of the angels. Now, he is with them. With his commitment to his family and public service, his life has truly blessed America.

'All who were blessed to know and to love Tommy mourn with his wife Margaret, his children Thomas, Dominic, Nicholas, Patricia and Gregory, and his grandchildren whom he adored, and are praying for them at this sad time.'

A spokesman for Pelosi said D'Alesandro died Sunday. He is pictured in 2010

In this 1968 photo then Baltimore mayor Thomas D'Alesandro looks at the ruins of a Baltimore building, one of many that burned during a weekend of rioting in the city