Spare lithium-ion batteries will no longer be allowed in checked baggage on airlines as of April 1, the UN's aviation agency said on Friday, following concerns by pilots and plane makers that they are a fire risk.

The batteries, which are rechargeable and used in cell phones or laptops, can only be packed in carry-on baggage or carried by the passenger, the International Civil Aviation Organization said in a statement. Lithium ion batteries are allowed in personal electronic devices, whether in passengers' carry-ons or checked baggage.

On Monday, ICAO prohibited shipments of lithium-ion batteries as cargo on passenger aircraft, citing safety concerns.

Lithium metal batteries, which are used in watches and are not rechargeable, have already been banned on passenger planes globally.

ICAO's 36-state governing council said the prohibition would be in effect April 1 and would be maintained until a new fire-resistant packaging standard is designed to transport the batteries. Lithium-ion batteries can still be transported on cargo planes.

The new packaging standard is expected by 2018, ICAO Council President Olumuyiwa Benard Aliu said earlier this week in a statement.

The ban would be mandatory for ICAO member states.

Pilots and aircraft manufacturers are concerned that existing standards are not strong enough to contain lithium battery fires. – Reuters