MADRID: Spanish postal workers intercepted a death threat letter with two bullets enclosed that was mailed to the conservative head of the Madrid region, the Interior Ministry said late on Tuesday, just days after her hard-left rival in an election for the regional assembly received a similar threat.

The ministry said the threat against regional chief Isabel Diaz Ayuso was discovered in a mail processing hub in Catalonia. Another letter, also containing bullets, was sent to the chief of the Guardia Civil police, the ministry's statement said.

Election frontrunner Ayuso played down the threat, telling the 13 TV channel on Tuesday night: "These things must be faced with the importance they have: none".

Her reaction contrasted with that of her far-left rival Pablo Iglesias who last week received a similar letter with four bullets and used the incident to boost his campaign, clashing with the far-right party Vox after its representatives doubted the letter's authenticity.

The death threats have fuelled what have already been acrimonious campaigns for the May 4 election to the 136-seat regional assembly.

Since she was elected in 2019, Diaz Ayuso has been at loggerheads with the central government on many issues from social policies to the COVID-19 pandemic response, notably keeping bars and shops open to support Madrid's services-heavy economy, while other regions have shut non-essential activities.

The vote in the region around the capital, Spain's wealthiest, is seen as a mid-term test for Prime Minister Pedro Sanchez's ruling coalition, which is expected to fare poorly.

According to most polls, Diaz Ayuso's Popular Party is slated to win by a wide margin though she would need the support from the Vox party to secure an absolute majority.

The polls suggest Sanchez's Spanish Socialist Workers' Party could lose half of its seats, and the broader left, including the two far-left parties, Mas Madrid and Unidas Podemos, are unlikely to form an absolute majority.