British Prime Minister David Cameron's persistent refusal to hold direct talks with Spain on the question of sovereignty over Gibraltar "clearly contravenes" the relevant U.N. resolutions, the Spanish foreign minister said Tuesday.

Jose Manuel Garcia-Margallo criticized London's position during an appearance before the Senate.

Britain will not discuss ceding sovereignty to Spain without the consent of the residents of the Rock, Cameron said Tuesday in a message to mark Gibraltar's national day.

Madrid, however, says sovereignty is a matter exclusively for the Spanish and British governments, and points to a series of U.N. resolutions dating back to 1965 that say likewise.

"Spain does consider itself obliged by those resolutions, just as by all international legality," Garcia-Margallo told senators, reaffirming Madrid's claim to sovereignty over the Rock.

Gibraltar, a territory of 5.5 sq. kilometers (2.1 sq. miles) at the entrance to the Mediterranean Sea, has been held by Britain since 1704 and became a British Crown Colony in 1713 under the Treaty of Utrecht.

Spanish Prime Minister Mariano Rajoy said last Friday that his meetings with Cameron during the G-20 Summit in Russia "laid the foundation for a dialogue" to address recent bilateral frictions over Gibraltar.

"Obviously whenever two people talk it produces a better situation than if those two people don't talk," Rajoy said. "It's evident that there is a problem and no one has an interest in having problems, and it's evident there has to be dialogue."

While calling for caution, the Spanish prime minister said he was confident the situation "will end well for everyone."

The latest flap over Gibraltar, a British Overseas Possession sitting at the tip of the Iberian peninsula, began when the local administration on the Rock dropped 70 concrete blocks into the Mediterranean with the aim of forming an artificial reef.

The reef project violates the European Union's environmental regulations and threatens the livelihoods of Spanish fishermen, according to Madrid, which imposed new border checks that have led to hours-long waits for people entering and leaving Gibraltar.

Responding to individual complaints from Spain and Britain, the European Commission launched separate probes of the reef project and the new border controls.

Gibraltar "will always be British," the Rock's chief minister, Fabian Picardo, said Tuesday. EFE