Boeing said Wednesday that India's defense ministry has signed an agreement with the US government to buy 10 Boeing C-17 transports, making India the plane's largest international customer.

Boeing said that under the deal, India will take delivery of its C-17 Globemaster III airlifters in 2013 and 2014.

The US aerospace giant's announcement followed unofficial news earlier this month that the big sale, approved by the US Congress in May 2010, was in the pipeline.

The biggest defense deal in history between the two nuclear powers "will elevate India's leadership in the region," Dinesh Keskar, president of Boeing India, said in the statement.

"With its tactical and strategic capabilities, the C-17 fulfills India's needs for military and humanitarian airlift," Keskar said.

"The important transaction reaffirms our close relationship of several decades with India and also highlights our commitment to the strategic partnership between the two countries."

Jean Chamberlin, vice president and general manager of Boeing Mobility, said the C-17's ability to handle large payloads, land on short runways, and operate in extremely hot and cold temperatures "makes it ideal for the region."

Boeing has delivered 232 C-17s worldwide, including 22 with international customers, according to the Chicago-based firm.

The bulk of them -- 210 -- were delivered to the US Air Force. Other customers include Britain's Royal Air Force, the Qatar Emiri Air Force, the Canadian Forces, the Royal Australian Air Force, the Strategic Airlift Capability initiative of NATO and Partnership for Peace nations, and the United Arab Emirates Air Force and Air Defence.

Separately, Boeing announced it will increase production of its Next-Generation 737 to 42 airplanes per month, beginning in the first half of 2014, to respond to "unprecedented" strong demand for the single-aisle jetliner.

The company raised the production rate three times last year for the latest version in the 737 family of commercial aircraft that it calls "the best-selling airliner in history."

It currently is building 31.5 Next-Generation 737s per month, and plans to boost that to 35 in early 2012 and 38 in the 2013 second quarter.

At the 42 per month rate in 2014, Boeing expects to build on average two 737s each workday and nearly 500 airplanes each year.

The newly announced rate increase was not expected to have a material impact on 2011 financial results, the company said.