ABUJA, Oct 21 (Reuters) - Nigeria has blocked the sale

of Shell's entire onshore and shallow-water oil and gas

assets in the Niger Delta, the country's upstream regulator said

on Monday, roughly 10 months after the deal was announced.

In a speech at an event in the capital Abuja, Nigerian

Upstream Petroleum Regulatory Commission (NUPRC) CEO Gbenga

Komolafe said the Shell deal "could not scale (the) regulatory

test," without elaborating.

A Shell spokesperson did not immediately respond to a

request for comment.

Shell said in January that it had reached an agreement

to sell its onshore oil and gas assets to the Renaissance

consortium of five companies for up to $2.4 billion, allowing it

to focus on deepwater and integrated gas investments.

The assets hold a combined estimated volume of 6.73

billion barrels of oil and condensate and 56.27 trillion cubic

feet of associated and non-associated gas.

In trying to exit the oil-rich Niger Delta, Shell

follows other oil majors Exxon Mobil ( XOM ), TotalEnergies

and Eni who wanted to do so because of

security concerns.

Environmental activists and some communities opposed the

Shell-Renaissance deal, tying Shell into a string of lawsuits

for environmental restoration and compensation for land and

rivers damaged by historical oil spills.

In April, the NUPRC started evaluating Shell's

divestment to the consortium, which comprises four Nigerian

exploration and production companies and an international energy

group.