Spain "has no respect for the jurisdiction or sovereignty" of British territorial waters around Gibraltar and is endangering lives through its reckless activity at sea, the Rock's Chief Minister has warned.
Fabian Picardo accused the Spanish Government of doing all it could "to create bad feeling" between the two countries.
His comments come as relations between the two neighbours have hit a new low after a Spanish customs vessel fired shots during a dispute with a pleasure boat last month in the latest in a series of incursions off Gibraltar.
Mr Picardo told the Press Association: "It demonstrates to us that Spain is not an ally, it demonstrates to us that Spain has no respect for the jurisdiction or sovereignty of British Gibraltar territorial waters, and it demonstrates to us that the founding principles of a good, strong relationship and partnership are not there.
"She is not trying to assert her rights in a peaceful way at a tribunal, she is putting people's lives in danger by shooting live rounds."
He accused the Spanish of "recklessness and negligence".
And he said that while Britain and Gibraltar remain "at the table" and willing to talk in trilateral discussions aimed at improving relations - Spain has "got up and left".
Mr Picardo made the comments following a rally to mark Gibraltar National Day, which celebrates the day Gibraltar first voted to stay British.
Thousands of locals wearing their national colours of red and white descended on the town square to celebrate.
Mr Picardo said the current Spanish Government is not interested in having a dialogue with Gibraltar or creating better relations between the neighbours.
He said: "They simply want to foster confrontation. That is unfortunate. That achieves nothing. It is very unfortunate indeed."
And the Rock's future could face further difficulties if Britain decides to leave the European Union.
Around 10,000 Spanish workers cross the border to work in Gibraltar every day.
But if the UK votes to leave the EU and the European single market then Gibraltar's economic future would need a "serious" rethink, Mr Picardo warned.
He said: "If the decision is for it to withdraw from the single market that would have serious potential economic consequences for Gibraltar and we would have to rethink our economic strategy."