LONDON (Reuters) - Britain condemned what it called "provocative incursions" into waters around the British territory of Gibraltar by Spanish navy and customs ships, and summoned Spain's ambassador on Thursday to express its concern over the issue.

The spat is part of a long-running dispute over Gibraltar, a peninsula in southern Spain ceded to the British in 1713.

Britain's Minister for Europe David Lidington noted two "serious incursions" into Gibraltar's waters on Tuesday.

"The UK has repeatedly made diplomatic protests to Spain over attempts by Spanish state authorities to exercise jurisdiction in British Gibraltar Territorial Waters," Lidington said in a statement.

"I condemn these provocative incursions and urge the Spanish government to ensure that they are not repeated," he said.

British Foreign Office Permanent Under Secretary Simon Fraser has summoned Spanish ambassador Federico Trillo, the Foreign Office said.

No one at Spain's Foreign Ministry or at the Spanish embassy in London was immediately available for comment.

Earlier this year, Spain accused police from Gibraltar of chasing its fishermen from Spanish waters and deployed Civil Guard officers to protect their boats.

Gibraltar and Britain said the police were enforcing fishing laws within their waters.

Spain's Queen Sofia pulled out of a lunch to celebrate the diamond jubilee of Britain's Queen Elizabeth earlier this year as the dispute escalated.

Spain's centre-right government led by Mariano Rajoy has taken a strong line on Gibraltar, which houses traditional British red phone boxes, pubs and fish and chip shops.

(Reporting by Mohammed Abbas; Editing by Louise Ireland)