MUMBAI, Oct 7, 2008 (AFP) - Indian shipworkers on Tuesday staged protests across the country to show their solidarity with 18 sailors held hostage since armed pirates seized their vessel off Yemen last month.

Several hundred people, some with their faces covered, stood outside a state shipping department in Mumbai, holding banners demanding 'Bring Back Our Brothers' and slamming government inaction.

A National Union of Seafarers of India (NUSI) official told AFP similar protests took place in 12 states across India.

NUSI general secretary Abdulgani Serang told a news conference that the union had written to Indian prime minister Manmohan Singh to demand the safe release of all on board the Hong Kong-registered MV Stolt Valor.

They called for the Indian government to provide escort ships to Indian-flagged and manned vessels in the volatile Horn of Africa, particularly off the coast of Somalia, a notorious hotspot for pirate attacks.

Ship workers and family members of the Indians on board have criticised the government for not doing enough to secure the release of their loved ones, nearly four weeks after they were first seized.

Seema Goyal, whose husband P.K. Goyal is captain of the MV Stolt, told reporters: 'It's 24 days now. People on board are undergoing mental and physical torture.

'We want our people back as soon as possible... We want a concrete result, a concrete answer to this now. We want our people back,' she added, flanked by relatives of eight of the crew.

India's defence minister A.K. Antony said last week 'serious attempts' were being made to end the hijack.

S. Hajara, the chairman and managing director of the Shipping Corporation of India Limited, said Tuesday he had spoken to Goyal on board the Japanese-owned ship, which is now anchored off the east coast of Somalia.

Despite being safe and having enough fresh drinking water, Hajara said the skipper had told him the hijackers were refusing to release the 22-strong crew, which includes two Filipinos, a Bangladeshi and a Russian.

The Indian government's nautical adviser, Captain M.M Saggi, added that a resolution could take time and cautioned that previous incidents had taken between six to eight weeks to end.

'It's a game of wits with the hijackers. It's who blinks first. Nobody wants to settle for less money. That's why these demands take so long,' he added.