It said, the prediction is lower due to recent increase in oil prices and the tightening of global financial conditions.
Lagarde spoke as a global market sell-off rolled into Asia following Trump's comments, underscoring rising financial volatility that the International Monetary Fund will address at its annual meetings with the World Bank this week in Bali.
Based on the trade tariffs already in place, the organisation revised down its estimates of world growth this year and next by 0.2 of a percentage point to a still healthy 3.7 per cent.
Meanwhile, rising interest rates are also pressuring some emerging markets with capital outflows, notably Argentina, Brazil, Turkey and South Africa.
"An IMF team will visit Islamabad in the coming weeks to initiate discussions for a possible IMF-supported economic programme", Lagarde said in statement. The most recent was in 2013 when Islamabad got a $6.6 billion loan to tackle a similar crisis.
The euro zone's 2018 growth forecast was cut to 2% from 2.2% previously, with Germany particularly hard hit by a drop in manufacturing orders and trade volumes.
The IMF expects the USA economy to grow 2.9 per cent this year, the fastest pace since 2005 and unchanged from the July forecast. It had previously predicted jobless rates of 5.5% and 5.2% respectively.
Pakistan began exploring the possibility of yet another loan package with the International Monetary Fund while the Pakistan Muslim League (Nawaz) PML-N was still in power and the exploratory talks continued under the interim government as well, it said. It now expects the global economy to only expand by 3.7% in 2018 and 2019, down from 3.9% before. These policies have contributed to a slowdown in economic growth, which is happening just as trade tensions with the USA are starting to bite.
"While foreign investors play a critical role in financial deepening in emerging market economies, excessively high levels of participation may increase the sensitivity of emerging asset markets to external shocks", the report said.
"Clearly as a result of (rate hikes). we see and we will continue to see capital flow movements", she added.
"We are all deeply concerned about this news and the potential impact on the business. And we've canceled a couple of meetings because I say they're not ready to make a deal".
SBP spokesman Abid Qamar told Reuters "the market is aware about the overall macroeconomic conditions and based on those conditions, they are having their own expectations about the exchange rate, so that is driving (the rupee valuations) now".
The Briton Woode institution is also projecting growth of 1.9 and 0.8 percent for Nigeria and South Africa while it is predicting contraction of 0.1 percent for Angola.
The effects on the U.S. and China would be particularly severe, with 2019 GDP losses of more than 0.9% in the USA and 1.6% in China in 2019. In September, Trump imposed tariffs on almost $200 billion of Chinese imports, with China responding with higher tariffs on about $60 billion of USA imports.
It also assumes that Trump imposes a 25% tariff on imported cars and auto parts imports.