ROME (Reuters) - Britain and France clashed again in a post-Brexit fishing row on Sunday, with London denying it had shifted its position and Paris insisting it was now up to Britain to resolve a dispute that could ultimately hurt trade. The two sides painted different pictures of a meeting between Prime Minister Boris Johnson and President Emmanuel Macron on the sidelines of a Group of 20 summit in Rome. Johnson said Britain"s position was unchanged but added he had been "puzzled" to read a letter here from Paris to the European Union asking "for Britain to be punished for leaving the EU". “I don’t believe that is compatible either with the spirit or the letter of the Withdrawal Agreement of the Trade and Cooperation Agreement and that’s probably all I’ll say about that,” he said, referring to the Brexit divorce and trade deals. Macron, also speaking at a post-summit news conference, said he wanted a deal. “I don’t want escalation. We need to be serious,” he said in Rome. “I don’t want to have to use retaliation measures, because that wouldn’t help our fishermen.” Macron said Paris had given proposals to London and “now the ball is in Britain’s court.” London has called on Paris to move first. The dispute was triggered when France accused Britain of issuing only half the fishing licences it believes it is entitled to. London says it distributes licences to fish in its waters under the rules provided in the Brexit deal. The row intensified when the French detained a British scallop dredger this week. Relations between Britain and France have become increasingly strained since Britain voted to leave the EU in 2016. London’s recently struck security pact with the United States and Australia did little to build trust with Paris. The fishing issue dogged Brexit talks for years, not because of its economic importance but because of its political significance. If not resolved, it could trigger the beginning of dispute measures in the Brexit trade deal as soon as this week. After Johnson and Macron met on Sunday, a French official said the leaders had agreed to try to de-escalate the row, which risks distracting from Britain’s hosting of the United Nations COP26 climate talks that start this week in Glasgow. But Johnson’s spokesman rejected the description of the meeting. Paris has said it could impose targeted measures from Tuesday, including heightening some checks, if there is no resolution to the dispute. A French official said earlier on Sunday that the two sides would try to work out ways to de-escalate the situation. “We’ll see on Nov. 2. We’re not there yet,” the official said. Reporting by Elizabeth Piper and Michel Rose; Editing by Crispian Balmer, William Schomberg and Frances Kerry