Mali sets April deadline to quell rebellion

* International calls mount for ceasefire

* Malian president under fire at home

BAMAKO Feb 11 (Reuters) - Mali is determined to quell a heavily armed Tuareg rebellion in its north before an election scheduled for April, the defence minister said on Saturday.

Dozens have been reported killed and thousands of civilians forced from their homes since the rebels, boosted by ethnic allies who returned to Mali after fighting for Muammar Gaddafi in Libya, started attacking towns and army bases last month.

The upsurge of fighting in an area already struggling to tackle the presence of local al Qaeda agents has raised concerns that the presidential election might have to be postponed.

"We have a mission which is very restricted in time. The elections are in three months and we need to have a solution in this short timeframe," Defence Minister Sadio Gassama told national radio from the northern town of Gao during a visit to troops.

"The men (in the army) are determined to make sure we can settle this problem in a very short time," he added.

President Amadou Toumani Toure, who has pledged to step down as leader of the West African country after the election, has faced a wave of domestic anger for not doing enough to crack down on the rebellion.

The United Nations and allies including former colonial power France have called for a ceasefire and negotiations, though they have backed Mali's rejection of the rebels' goal of outright independence for three northern regions.

The fighting is the most serious fallout yet from the Libyan war on the fragile Sahel region, whose resources include gold, oil and uranium.

Last weekend, rebels came within 8 km (5 miles) of Kidal, the capital of one of the three regions they are seeking to control. But a Malian military official said they have since been pushed back by helicopter gunships, as well as heavy weapons fire by the armed forces. (Reporting by Tiemoko Diallo; Writing by Mark John; Editing by Alessandra Rizzo)