and its main airport ahead of Thursday's vote to elect a president of the semi-autonomous region, a senior regional official said Tuesday.

"We have closed all the approaches to Kismayo to prevent the Somali federal government, which is using all possible ways including Ethiopian forces, to disrupt the Jubbaland election," Mohamud Sayid Aden, vice president of Jubbland, told Reuters.

The move underscores escalating tensions between Jubbaland authorities and the federal government in Mogadishu, who have been seeking to exert control over the election process in the last month.

On Saturday the Somali government said it would not recognize the result of the election in Jubbaland, a key battleground state for counter-terrorism operations, saying the candidate selection process violated the national constitution.

The stand-off risks sparking a dangerous wider conflict.

Incumbent Jubbaland President Ahmed Mohamed Madobe, who is seeking re-election this week, is a key security partner for Kenya, while Ethiopia has grown closer to the federal government in Mogadishu in the last year.

Both Ethiopia and Kenya have significant numbers of peacekeepers in Somalia.

A split between them would undermine international counter-terrorism operations against al-Qaida-linked Islamists al-Shabab, security analysts say.

VOA