BUDAPEST, May 16 (Xinhua) -- A three-day meeting of the NATO Parliamentary Assembly got underway in Budapest on Saturday, with Russia and anti-terrorism likely to take top slots on the agenda.

Hungarian Defense Minister Csaba Hende addressed the Defense and Security Committee, one of the three committees meeting on Saturday.

Security in Europe has significantly deteriorated, Hende said, noting the wave of refugees from the Middle East and North Africa flooding the eastern and southern European countries.

The western countries are facing a steadily growing challenge because of this, he added.

The minister said the instability in the Middle East favored the rise of extremism. He said the Islamic State was also a threat to Europe, adding that Europe had to prepare for possible terrorist attacks.

NATO responded well, Hende said, becoming tighter-knit and stronger with an increased budget as resolved by last year's NATO summit in Wales.

Hende then pointed to Hungary's neighbor Ukraine, saying that the armed conflict there had erupted very suddenly and unforeseeably.

The Economics and Security Committee and Science and Technology Committee also met on Saturday. The Civil Dimension of Security and the Political Committees will meet on Sunday, while Monday will be reserved for a plenary session.

NATO established its Parliamentary Assembly in 1955. Members are delegated by the national parliaments of the member countries. NATO currently has 28 members.