Washington - Silvio Berlusconi, the Italian prime minister, called on Wednesday for “a grand alliance of all democracies” to fight the threat posed by Islamic extremism, telling a rare joint session of the US Congress Italy would stand by the US in that effort.

Television channels owned by Mr Berlusconi’s Mediaset broadcast his speech in Italy, provoking objections from some opposition leaders, who accused the prime minister of improper bending of Italian equal-airtime regulations during election campaigns. Some US Democrats also made known their objections to what they saw as improper use of Congress to boost Mr Berlusconi.

Mr Berlusconi, in the middle of a troubled election campaign, is one of just seven foreign leaders accorded the honour of addressing Congress since George W.Bush became president in 2001.

With the exception of Manmohan Singh, Indian prime minister, whom Mr Bush is visiting this week, the president has reserved the privilege for Washington’s closest allies in the war in Iraq.

These have included Tony Blair, UK prime minister, José María Aznar, former Spanish premier, Viktor Yushchenko, Ukrainian president, Hamid Karzai, president of Afghanistan, and Ayad Allawi, the former Iraqi interim prime minister.

Mr Berlusconi and Mr Bush have maintained a warm personal relationship in spite of Italy’s decision to begin withdrawing troops from Iraq this year. Following a meeting on Tuesday before Mr Bush’s departure for Asia, the president called Mr Berlusconi “a strong leader” and a “man of his word” who had brought stability to Italy’s government.

Returning the praise, Mr Berlusconi said the world was “lucky because the biggest democracy in the world has such a leader who sees problems affecting the world so clearly”.

The US trip is likely to provide a much-needed political boost for the Italian premier ahead of parliamentary elections on April 9 and 10.

Opinion polls show his centre-right government trailing the centre-left opposition, led by Romano Prodi, by several percentage points.

This year’s election will be the first time Italians living overseas will have a chance to elect their own members of parliament in designated foreign constituencies, totalling 12 out of 630 members in the lower house.

Despite opinion polls that show many Italians have a poor view of the US, Mr Berlusconi has not been shy in stressing his close ties to the Bush administration.

In his address to Congress he said he had been inspired by US support for Italy over the decades to respond by sending Italian forces to Afghanistan, Iraq and the Balkans.