Islamist militant group Boko Haram is believed to be getting ready to launch a large scale attack ahead of general elections on February 14, beginning in the strategic city of Maiduguri in northeastern Nigeria.

On Sunday, Boko Haram attacked and attempted to capture the city, which is the capital of the Nigerian state of Borno, as US Secretary State John Kerry visited Lagos to confer with top presidental candidates Mohammadu Buhari and Goodluck Jonathan, the incumbent president.

The Nigerian Army managed to defeat and push back the militants from the state capital. However, Sahara Reporters reports that sources within the Nigerian security officials revealed the militants are massing their forces once again for another try at capturing Maiduguri.

Boko Haram's activities have escalated as general elections approached. The group also expanded its activities into neighbouring countries like Cameroon, prompting other countries like Niger and Chad to join the efforts in curbing the group's activities.

"We have received tips from some of the locals that they have sighted the militants," a security operative in the beleaguered city told Sahara Reporters' correspondent. Villagers allegedly saw Boko Haram soldiers travelling through Dikwa in SUVs, camels and motorcycles, the anonymous operative said.

In addition, former US Ambassador to Nigeria John Campbell told Newsweek that, while Boko Haram may have been foiled in its first try to capture the city, the group was also effectively surrounding the city when it captured several villages in its vicinity.

"In terms of the encirclement of Maiduguri, we try to track the villages that Boko Haram occupies around Maiduguri and indeed it looks like a noose," Mr Campbell explained.

Mr Campbell is the editor of the Nigeria Security Tracker, which tracks occurrences of violence in the country.

The former ambassador told Newsweek that Boko Haram may be compelled to focus its attacks on important parts of the city like the airport because of its limited manpower. However, he said, it is also possible that the militants could engage in a "massacre" of people that are associated with the current government.

"The people I think would be the prime targets [of a Boko Haram offensive] would be officials, police, maybe teachers in secular schools, people like that," Campbell opined.