March 8 (Reuters) - John Menzies is still in talks with a potential Kuwaiti suitor and has given it a March-end deadline to make a firm offer, the British airport services group said on Tuesday and reported a swing to annual profit.

NAS, owned by Agility Public Warehousing Co, has been building up its stake in Menzies in the past weeks. It had made a proposal of 608 pence a share to buy the company on Feb. 21 and had until Wednesday to make a firm offer for the firm.

However, Menzies said on Tuesday the deadline for the Kuwaiti provider of aviation services has been extended to March 30.

The company also posted underlying operating profit for the year ending Dec. 31 of 76 million pounds ($99.54 million), compared with a loss of 24 million pounds a year earlier.

Edinburgh-based Menzies, which is among the biggest providers of fuelling, ground handling, and maintenance services with operations in around 38 countries, had suffered heavy pandemic-led losses in 2020 but has since recovered on cost cuts and restructurings.

While it does not expect to return to pre-pandemic levels until 2024, the group said it sees the steady rise in passenger air travel to pick up this year and beyond, helping bolster revenue for its fuelling and ground services business.

John Menzies now targets net new revenues of $100 million this year and about $200-275 million over the short-to-medium term.

The company, which operates at more than 200 airports globally, added that it is monitoring the wider impact of Russia's invasion of Ukraine on air travel but it was difficult to assess at this time. It does not operate in either countries. ($1 = 0.7635 pounds) (Reporting by Yadarisa Shabong in Bengaluru; editing by Uttaresh.V)