LISBON (Reuters) - Drought-hit Portugal asked the European Union on Saturday for aircraft to fight forest fires raging across the nation, a fire service spokeswoman said.

Officials asked Brussels to supply amphibious planes and helicopters and are awaiting a response.

About 3,600 firefighters were battling nearly 50 fires on Saturday, the fire service said. Portugal is suffering its worst drought on record. Clouds of smoke hung over Lisbon.

The most serious fire was near Pampilhosa da Serra, in central Portugal, and was being fought by about 200 men. The blaze reignited on Friday after firefighters struggled for five days to put it out.

Forest fires have burnt about 134,500 hectares (337,000 acres) of woodland, the forestry service estimates.

At least 13 people have died from fires this year, 10 of them firefighters, Lusa news agency said.