BRUSSELS, Feb 6 (AFP) - International condemnation mounted Sunday over a "military coup" in Togo after the death of President Gnassingbe Eyadema, Africa's longest-serving ruler.

The African Union (AU) and the ECOWAS regional grouping both called for the country's constitution to be respected, while the European Union -- a key provider of funds -- warned any unconstitutional action will threaten aid.

"The greatest homage that the people of Togo could render (Eyadema) for his services to west Africa is a peaceful transition," said the 15-member Economic Community of West African States (ECOWAS) after Eyadema's death Saturday.

AU Commission president Alpha Oumar Konare was uncompromising in condemning events in Lome.

"What's happening in Togo needs to be called by its name: it's a seizure of power by the military, it's a military coup d'etat," he said late Saturday, hours after Eyadema's death.

President Eyadema, who had governed virtually unchallenged for nearly four decades, died Saturday while being flown to France for emergency medical treatment. He was 69 years old.

The Togolese armed forces immediately installed in power one of the late president's sons, Faure Gnassingbe, although the country's constitution called for the speaker of the National Assembly to become interim president until a new head of state is elected within two months.

On Sunday, Togolese lawmakers gave backing to Faure's appointment, voting him the new parliament speaker and amending the constitution to eleminate the requirement to hold new elections and allow him to serve as president until his father's term ends in 2008.

ECOWAS executive secretary Mohammed ibn Chambas and Niger President Mamadou Tandja, current ECOWAS chairman, had strongly condemned the violation of the Togolese constitution.

Chambas "urged the political class in Togo to apply wisdom and expressed his wish that current talks among all parties could continue so that peace, stability and unity, described as legacies of Eyadema, could be preserved," said a statement.

In Brussels, EU aid commissioner Louis Michel warned that relations between Lome and the EU -- and funds supplied by the EU -- would suffer unless the constitution was followed.

"I call for the strict respect of procedures foreseen by the constitution. Anything else could only bring into question .... the prospect of improvements in relations with the European Union," he said.

An EU source said this was code for the unblocking of over 40 million euros (52 million dollars) in aid. "They should not dream of any resumption of aid if the solution they're finding now is without a constitutional basis," said the source.

The EU, along with France the key aid donors to Togo, partially resumed diplomatic ties with the west African state last November, after cutting off cooperation with Lome in 1993 because of a violence and a lack of democracy

The United States on Sunday urged Togo to respect its constitution and hold elections to replace Eyadema.

"The United States urges all Togolese to respect strictly the constitutional process of Togo, which will lead to elections for a new president," US State Department statement deputy spokesman Adam Ereli said in a statement.

The EU source said that the immediate danger was of a serious political crisis, but did not rule out violence if the situation was not resolved rapidly.

Other African countries, many of which had hoped that military coups were becoming a thing of the past, are all too aware of that risk.

In Dakar, the International Federation of Human Rights Leagues (FIDH) and the Togolose Human Rights League (LTDH) both "fiercely condemned this military coup d'etat and demanded an immediate return to constitutional order."

The head of International Organisation of the Francophonie (OIF), former Senegalese president Abou Diouf called for the "rigorous application" of the Togolese constitution.