ROME (AP) _ Two men sought for seven years for a series of gangland murders in southern Calabria were arrested today in the countryside outside the city of Reggio Calabria.

After recent blows by the state against the Sicilian Mafia and the Camorra in Naples, the arrests were a major strike at Italy's third leading gang, the Calabrian 'ndrangheta.

Police also said they may have thwarted a plan to blow up the Justice Palace, housing the offices of prosecutors and judges in Palermo, Sicily, with the arrests of two men over the past few days. The men were picked up in Milan and Palermo after police intercepted telephone conversations about a bombing, news agencies said.

Arrested in the Calabrian operation were Antonio Imerti, 46, known as ''nano feroce'' (''ferocious dwarf'') - he's 5-foot-5 - and his brother-in- law, Pasquale Condello, 30.

They were both armed with pistols but put up no resistance when police surrounded them as they were walking to a hideout at around 2 a.m., news reports said.

Both men had been convicted in absentia, and face life imprisonment.