The world's top brewer Anheuser-Busch InBev said Wednesday its first quarter profits fell due to weakness in the Brazilian market but that its acquisition of SABMiller was on track to be completed this year. 

Revenues fell 10 percent to $9.4 billion compared with the same period last year, the Belgium-based group said in a statement. 

The group, which is awaiting to hear later this month whether the European Commission has approved its buyout of British rival SABMiller, said it remained "cautiously optimistic" for the rest of the year. 

"We are making good progress towards obtaining the necessary regulatory clearances for the proposed combination with SABMiller," the company said. 

"We continue to expect the transaction to close in the second half of 2016." 

If the $122-billion buyout, which was announced in November, gets the green light, it would be the third largest acquisition in history, bringing together AB InBev brands such as Corona, Stella Artois and Budweiser with SABMiller's Czech brand Pilsner Urquell. 

At the start of the first quarter, AB InBev registered a drop in sales in its North and South American markets where it conducts more than half of its activities. 

"Total volumes declined by 1.7 percent, with our own beer volumes down by 1.4 percent. The decline in own beer volumes was driven by Brazil which, as expected, faced challenging macroeconomic conditions and a difficult comparable, partly offset by strong results in Mexico," it said. 

"Our beer volumes in Brazil declined by 10 percent due to a tough comparable driven mainly by a very challenging macroeconomic environment in comparison to the first quarter last year." 

In order to ease competition concerns and win approval from European regulators, the Belgian-Brazilian brewer said it would offload SABMiller's European concerns, and announced last month the sale of the Peroni and Grolsch brands to Japanese beer giant Asahi Group.

AB InBev sees the buyout of SABMiller as a key way to counterweight falling beer demand in big markets by building its presence in Africa and other regions where sales are going up.