London- Qatar Airways has bought a stake worth about $1.7 billion in the owner of British Airways and Iberia, aiming to forge closer links to a group with two major European hubs and strong transatlantic networks.

The Gulf airline, which disclosed a 9.99 percent holding on Friday, already partners International Consolidated Airlines Group in the oneworld alliance and has limited code-sharing deals and a freight partnership with BA.

Buying the stake could deepen the relationship, giving Qatar greater access to destinations served by IAG's London and Madrid hubs, particularly transatlantic, with North America well served by British Airways and South and Central America by Iberia.

On IAG's part, the tie-up will create opportunities in southeast Asia, India and the Middle East, where Qatar has an extensive network, while also giving it a wealthy long-term backer whose support could be useful in funding future growth.

Neither party said whether IAG had been aware Qatar was building the stake and did not say who the shares had been bought from, or when. But IAG Chief Executive Willie Walsh said he was "delighted" to have the airline as a supportive shareholder.

Qatar's national airline, which has more than 130 aircraft and 340 on order, said it may consider increasing its stake over time, although it was not currently intending to increase it from 9.99 percent.

Non-European shareholders of IAG are subject to a cap because of a requirement for EU airlines to be majority controlled by EU shareholders.

Owned by the country's sovereign wealth fund, Qatar Airways has become a major global carrier alongside regional rivals Emirates and Etihad Airways.

All three have used huge capacity at Middle East hubs to challenge European airlines in the long-haul market. Qatar's visibility in Europe has been strengthened by a sponsorship deal with Spanish soccer club Barcelona.

Owing to their geographic position, however, the carriers have struggled to make a mark on routes to North America.