(Reuters) - Yemen's powerful Houthi movement fought artillery battles with the army near the presidential palace in Sanaa on Monday, throwing the fragile Arab state deeper into turmoil and drawing accusations that the militia fighters were mounting a coup.

Explosions echoed across the city and smoke hung over downtown buildings as the most intense clashes since the Shi'ite Muslim Houthi movement seized the capital in September brought everyday life to a halt.

The Houthis had seized the state news agency and television station, but by evening a ceasefire was in force, government ministers said.

Medical sources said five people had been killed and more than 20 wounded. Final numbers were likely to be higher.

The battles marked a new low for Yemen, plagued by tribal divisions, a separatist challenge in the south and the threat from a regional wing of al Qaeda, which claimed a deadly Jan. 7 attack in Paris on a satirical journal known for mocking Islam.

The Houthis' September takeover made them the country's de facto top power, a development that has scrambled relationships and raised tensions across the political spectrum ever since.

Information minister Nadia al-Saqqaf, a critic of the Houthis, told Reuters the presidential palace had come under "direct attack" in what she described as an attempted coup.

"If you attack the presidential palace ... This is aggressive, of course it is an attempted coup," she said.