Ethiopian troops cross into two Somali towns-locals

* Residents say troops seeking man linked to insurgents

* Say troops seize family of man they sought

By Mohamed Ahmed and Abdi Sheikh

MOGADISHU, Feb 7 (Reuters) - Ethiopian troops in armoured vehicles crossed into two border towns in south central Somalia and seized the family of a man with links to al Shabaab insurgents, residents said on Sunday.

They said troops went to El Barde and Yeed on Saturday seeking the man. Washington says al Shabaab is al Qaeda's proxy in the region and which has declared loyalty to al Qaeda.

"Ethiopian troops entered El Barde yesterday and arrested several people today. They were onboard armoured vehicles and were searching for a well-known local man who also works with al Shabaab," a town resident, Hussein Ronow, told Reuters.

"The man escaped, but they took with them his wife and three children. They also took the escaped man's brother and family. The troops have now gone but I understand they are in the outskirts of the town."

Ethiopia invaded its Horn of Africa neighbour with tacit U.S. support at the end of 2006 to oust an Islamist movement that was running the capital Mogadishu and much of the south.