MENDOZA, Argentina, July 19 (Xinhua) -- A summit of Mercosur (Southern Common Market) nations kicked off on Wednesday with a push to form a pact with newer Latin American trade bloc, the Pacific Alliance.

The gathering being held in Argentina's north-central city of Mendoza, opened with a seminar that analyzed the need for an agreement with the Pacific Alliance parallel to the one being negotiated with the European Union.

The leaders of Chile, Argentina, Brazil, Uruguay and Paraguay are expected to arrive in Mendoza starting Thursday for Mercosur's first summit in a year and a half, which comes amid tension sparked by the divergent political currents of its member countries.

Since Brazil and Argentina have come under conservative leadership, they have clashed with also member Venezuela and its ruling socialist government. Venezuela was suspended from Mercosur, after which it announced it was withdrawing from the trade and integration bloc.

The infighting has weakened the bloc, making an alliance with the the Pacific Alliance, which gathers Mexico, Chile, Colombia and Peru, all the more attractive.

Strengthening the alliances between the different trade blocs will be one of the main points on the agenda at the Mercosur summit," said the Mexican news agency Notimex.

The leaders' summit will be held on Friday, culminating with a joint declaration.

Argentina, which took on the bloc's rotating presidency after Venezuela was stripped of the role, will be handing the reins over to Brazil.