LONDON, Sept 13 (Reuters) - Sales at fashion retailer Primark fell short of management expectations in its latest quarter, hit by public health restrictions in major markets to control the fast-spreading Delta coronavirus variant. Shares in owner Associated British Foods (ABF.L) were down 3.4% at 0859 GMT after it forecast Primark"s like-for-like sales in its fourth quarter to Sept. 18 were down 17% on the same period two years ago. That was after a 3% increase in the third quarter when stores reopened from pandemic lockdowns. Primark"s two biggest markets, Britain and Spain, were particularly badly hit. Britain suffered in late June and early July from a surge in the number of people self-isolating following contact tracing alerts - the so-called "pingdemic". Spain was hurt by the decline of foreign tourism. The group said Primark, which does not trade online, did see an improvement from a weekly decline in like-for-like sales of 24% early in the quarter to a drop of 10% in recent weeks. Finance chief John Bason said Primark maintained its market share and was optimistic about key Christmas trading. He noted delays with some autumn/winter inventory caused by port and container freight disruptions - part of supply chain problems across Britain due to a shortage of lorry drivers. But he said stores were not short of product. "Is it easy in the supply chain? No ... but it"s about delays rather than cancellations," he told Reuters. read more And despite the shortfall in Primark"s sales, the group raised its profit outlook for the 2020-21 financial year, reflecting strong profit margins at the fashion business - due to a significant reduction in labour and store operating costs - and a robust performance from its food and sugar operations. It forecast full-year adjusted operating profit before the repayment of government job retention money, above last year"s 1 billion pounds ($1.4 billion), excluding the benefit of a 53rd week this year. It had previously forecast an outcome in line with the previous year. ($1 = 0.7233 pounds)