Thailand extended a tough security law on Tuesday for another week after opposition protest leaders called for a “historic rally” to paralyse Bangkok in a bid to force an election that appears no closer to succeeding.

Tens of thousands of protesters remained at their open-air encampment in their trademark red shirts, calling for Prime Minister Abhisit Vejjajiva to dissolve parliament in a rally that has now entered its second week.

Security concerns were highlighted when two grenades exploded in the compound of the Public Health Ministry, about 1 km (0.6 miles) from where the cabinet had earlier met.

The usual venue, Government House, has been avoided because of its proximity to the protests. The explosions, like previous incidents, were not blamed on the “red shirts” and caused no injuries.

Protest leaders, allied with ousted Prime Minister Thaksin Shinawatra, have not revealed details of their plans for the rally on Saturday and whether the demonstrators will fan out across the city as at least 65,000 of them did at the weekend.

“The cabinet sees that there is still a need to be vigilant,” Abhisit told reporters, adding the law has been extended until March 30 for Bangkok and some surrounding districts.

The rally has so far been orderly. Most analysts say the protesters are likely to struggle to maintain momentum and expect Abhisit to prevail because of the support he enjoys from the majority of parliament, the powerful military and Bangkok elite.

These factors have encouraged continued fund flows into Thai assets, pushing Thai stocks to around a 20-month on Tuesday, drawn by cheap share prices and high dividend yields.

The bourse closed up 1.3 percent on Tuesday, when foreign investors bought a net 1.88 billion baht ($58.17 million) of shares, raising their net purchase to about 42.16 billion baht ($1.3 billion) in the last month.

Abhisit has refused to call an early election, which the Thaksin-allied Puea Thai Party would be well-placed to win. That scenario presents a risk to investors and raises the chance of another judicial or military intervention to keep Thaksin and his allies out of the corridors of power.

DEEP DIVISIONS

Abhisit insists the deep political divisions would undermine any chance of peaceful polls if an election were held now. His critics say he and his backers are clinging on to power.

Puea Thai on Tuesday followed the “red shirts” in calling for parliamentary dissolution. Members planned to meet partners in Abhisit’s uneasy coalition to discuss a political solution, said party chairman Chavalit Yongchaiyudh.

Key coalition partners reiterated their stance on Tuesday that they have no plan to break away from the alliance amid speculation that Puea Thai would try to bring them on board.

The Internal Security Act gives the country’s powerful military-led security agency, the Internal Security Operations Command, an option to impose curfews, operate checkpoints and restricts movements if protests turn violent.

Political analysts say the longer the protesters are on the streets, the greater the risk a frustrated minority could break ranks and spark sporadic unrest, as they did in April 2008, denting Thailand’s image as a safe tourist destination.

Government spokesman Panitan Watanayagorn said there had been eight attacks involving explosives since the protest started on March 12, likely aimed at discrediting the government or causing confusion.

“We believe the perpetrators want to prolong the climate of fear to show the government is not in control,” Panitan said.

Protesters said the attacks were staged to discredit them.

On Tuesday, “red shirts” also rode on about 1,000 motorcycles around Bangkok to give out leaflets, urging city residents to join the rally.

Soldiers and police cordoned off areas around parliament and closed several roads ahead of a session which Abhisit is expected to attend on Wednesday. He has steered clear of his office, his home and parliament since March 12, instead working out of a military base which also doubles as a safe house.

(Writing by Ambika Ahuja; Additional Reporting by Viparat Jantraprapaweth; Editing by Martin Petty Editing and Alex Richardson)