Lagos, Nigeria (CNN) -- Nigeria's Independent National Electoral Commission is urging would-be voters to turn out for the scheduled voter registration session in January, in hopes for a "free fair and credible elections in 2011," a Commission spokesman said Thursday. 

"This reassurance is necessary against the backdrop of the theft of some Direct Data Capture machines at the Lagos airport, " said Kayode Robert Idowu, a Commission spokesman in a press statement. 

On Tuesday, 20 voting machines were stolen at the Lagos airport, out of a total of 6,000 brought into the country by Zinox Technologies Ltd., Idowu said. Sixteen machines have been recovered so far and security agents are investigating the case, he said. 

The equipment, meant for registering voters for the upcoming election in Nigeria, is comprised of laptops and webcams. It was stolen from a clearing point at the Murtala Muhammed International Airport, said Idowu. 

The equipment was the first consignment ordered to help register voters for the 2011 elections. 

The presidential election is expected to take place in April 9. 

President Goodluck Jonathan, who became president after the death of Umaru Yar'Adua earlier this year, is running for election to the office. He will be challenged in the primaries by another former vice president of Nigeria. 

Atiku Abubakar is the consensus candidate put forward by a bloc of leaders from Nigeria's influential Northern Political Leaders Forum, which announced in September that it would name someone to take on Jonathan in the presidential primaries for the People's Democratic Party. 
What was stolen?
20 voting machines were stolen at the Lagos airport