Helios, which operates phone masts in Ghana, Congo Republic, Democratic Republic of Congo and Tanzania, said it had received "considerable interest" from institutional investors who liked its business plan and growth prospects.

However, without giving reasons, it said shareholders had decided to withdraw from the listing, which had been scheduled for next month.

The banker involved on the deal said investors were worried about the political and policy risks in Democratic Republic of Congo (DRC) and Tanzania.

"The valuation from market feedback was not enough for the shareholders. We had a lot of interest from investors but they wanted a discount for the political risk in DRC and Tanzania," the banker, who asked not to be named, said.

Millions died in a 1998-2003 civil war in Democratic Republic of Congo, and a deepening crisis over President Joseph Kabila, who was meant to leave office in 2016, is raising fears of the vast nation of 75 million people imploding once again.

Last month, the front cover of the influential Economist magazine carried a picture of heavily armed Congolese soldiers walking down a road below the headline "Heading back to hell".

Tanzania, by contrast, is politically stable but President John Magufuli, nicknamed the 'Bulldozer' for his style, has put off foreign investors with his heavy-handed attacks on the mining sector as part of an anti-corruption drive.

Helios is owned by telecom firms Millicom and Bharti Airtel and hedge funds including Albright Capital Management and Soros Fund Management, which owns more than 20 percent.

It was formed in December 2009 and owns around 6,600 towers in the four countries.

On March 2 it said it was targeting an IPO on the main market of the London Stock Exchange in early April.

Cape Town-based analyst Laura Graves of consultancy TowerXchange said another deal might be in the works, possibly involving Eaton Towers, which operates around 5,000 masts in Ghana, Kenya, Uganda, Niger and Burkina Faso.

The London-based firm has also been looking to list in London.

"There has long been speculation that Helios could look to merge with Eaton Towers," Graves said.

"With overlap only in Ghana, the two portfolios are largely complementary and when combined, a portfolio of over 11,000 towers in eight different markets would be an attractive asset due to its increased size and diversified risk profile."

(Reporting by Pamela Barbaglia, Dasha Afanasieva and Ed Cropley; Editing by Ed Cropley; Editing by Jason Neely and Mark Potter)