Caspian Sea country to tighten his grip on power, political analysts say.

Five officials from the division that is supposed to fight organised crime are themselves under arrest on serious charges.

Diplomats and political analysts already see signs that outrage over the scandal could prompt Aliyev to enhance his power and that of his son, Ilkham Aliyev, 36.

Some regard Ilkham Aliyev as his 75-year-old father's possible hand-chosen successor.

Aliyev railed against several of his ministers in recent meetings, according to the official press.

"He's coming down hard on a few of his ministers. He wants to clean house, and to bolster the Aliyev family image,'' said one foreign diplomat.

That image was dealt a blow by a disputed election last year which Aliyev says he won but opposition groups say was rigged. Add to this Aliyev's recent bout of ill health, lower oil revenues and some disappointing recent offshore Caspian drilling results of foreign consortiums.

There has also been talk of a rift at the upper levels of Aliyev's ruling New Azerbaijan party, denied by the leadership.

The oil difficulties have tempered years of heady optimism that the poor ex-Soviet republic was on a sure path to wealth.

Petrodollars had also been seen by Aliyev and his government as a way to rebuild Azerbaijan's humiliated army and be in a position to retake land lost to ethnic Armenian forces in fighting from 1988-94 over the disputed Karabakh region.

"Don't be surprised if we see the axe fall on some ministers fairly soon,'' said the diplomat, who said he nonetheless expected the defence, interior and security ministers to stay.

The sackings would also be a way to deflect criticism that the government has taken no steps to diversify away from oil.

One of those arrested, anti-organised crime unit chief Nizami Godzhayev, is a relative by marriage of parliament speaker Murtuz Aleskerov. Rumours of Aleskerov's impending removal have been circulating for weeks.

Godzhayev's lawyer says his client has been charged with the murder of the head of the state company which controls its lucrative caviar production.

Top opposition leader Etibar Mamedov, who finished second to Aliyev according to official results but accuses Aliyev of vote-rigging, said Godzhayev's arrest might create a pretext for removing Aleskerov.

"I wouldn't exclude that,'' Mamedov told Reuters.

Some independent newspapers have said Haydar Aliyev might try to replace Aleskerov with his son Ilkham, who is deputy head of state oil company SOCAR.

Under the constitution, the speaker would take over power should the president die in office.

There has been widespread speculation in Azerbaijan about a possible looming dynastic succession of sorts putting Ilkham Aliyev at the helm eventually.

Top New Azerbaijan officials have given them credence by publicly saying they back Ilkham as a future president.

The rumours have intensified since Haydar Aliyev spent two weeks in hospital earlier this year in Turkey for what has been described as a viral infection and bronchitis. Sources inside the ruling circle have said Aliyev suffers from heart problems.