Delta Air Lines announced plans to pay a higher price to boost its stake in its Mexican airline partner Aeromexico, launching a cash offer Monday for 53 pesos per share.

Atlanta-based Delta already owns about 4.2 percent of Grupo Aeromexico shares, holds options to buy another 12.8 percent and has had plans to increase its stake to up to 49 percent of outstanding shares. Delta last November announced plans to pay 43.59 pesos per share for 32 percent of the Mexican carrier’s stock.

The higher price in Monday’s offer for the Aeromexico stock is “the result of interim exchange rate movements and other factors,” according to Delta.

The 53 peso per share offer is equivalent to about $2.60 per share, and a premium to Friday’s closing price of $39.43. That would make the value of Delta’s purchase of 32 percent of Aeromexico’s stock an estimated $590 million.

Aeromexico’s share price rose more than 16 percent Monday morning after Delta’s announcement.

The deal must be accepted by shareholders of at least 25 percent of Grupo Aeromexico's stock, and is subject to antitrust approvals in Mexico.

“This is the next step in expanding our longstanding partnership with Aeromexico,” said Delta CEO Ed Bastian in a written statement.

Delta and Aeromexico launched a code-share marketing deal in 1994 and have deepened ties in the past few years. Delta bought a $65 million stake in Aeromexico's parent company in 2012.

The two carriers in 2014 opened a jointly-operated maintenance, repair and overhaul center called TechOps Mexico near Queretaro International Airport.

In 2015 they announced a deal to boost Delta's stake, along with options for Delta to buy more shares for a total of 49 percent of the company. Delta and Aeromexico last year agreed to federal terms for antitrust immunity to move forward with a joint venture.